Optiplex 790 & KFA2 and Galaxy GTX 750 Ti Low Profile - Will it work

TonyD123

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I have been looking for days at various threads recommending the HD7750 for a SFF optiplex 790 but the one by VTX on amazon has been discontinued.

So my question is: can/should I but the following low profile version of the GTX 750 by GALAXY/KFA2.

I have a 240Watt dell PSU with 17.0Amps on the +12volt rail and 0.8Amp on the -12v rail. I am aware the Mboard is restricted to about 25watt on this dell and given that the card requires no extra power connector can I assume it will draw all the power from the board? and, assuming that, can I assume that nothing will explode or (more likely) burn out?

As for the dimensions, it will be very, very tight and I think in fact the fan casing will be 1mm from the PSU - is this dangerous for the fan/PSU? should I remove the fan (of course voiding warranty) or just not buy the card.

Here is the link; I live in the UK.
http://www.overclockers.co.uk/showproduct.php?prodid=GX-058-KF&tool=3

Finally, can I actually get away with buying this card or would I be wasting my money?

Damn near 21 years old and I'm like a child at christmas, although to be fair this card is a 9 on GameDebate and along with my 9 CPU should make for a nice gaming machine, the size of a large lunchbox.

Thoughts please, especially vis a vis whether the PSU will be enough and whether it will be enough if I unplug the DVD drive on the dell and/or underclock/volt the card.

Regards,
Tony.
 
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Check out this .PDF file http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CCcQFjAA&url=http%3A%2F%2Fwww.dell.com%2Fdownloads%2Fglobal%2Fproducts%2Foptix%2Fen%2Foptiplex-790-tech-guide.pdf&ei=q71vU_o6z5PIBMKxgeAL&usg=AFQjCNFUPhX2KkAjWxhGllsqdzjniN3vSg&sig2=cLSr7laR_AS4iMojA5YHjQ&bvm=bv.66330100,d.aWw
It should be the Dell manual for all 4 sizes of Optiplex 790 PCs; Desktop, Mini Tower, Small Form Factor, and Ultra SFF. I presume yours is the Small Form Factor.

I had to check out the motherboard layout of the SFF model. I just couldn't believe it had a PCIe X16 slot and another PCIe X16 slot @ X4 electrically right next to it. But it does! (scroll down to page 7 & 8 for the SFF). I have never seen that...

clutchc

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I'm afraid not. That single 17A +12V rail is just too small. Even though it is billed as a 60W TDP card, the GTX 750 Ti can peak at nearly twice that during intense gaming. That would be 12A just for the card alone. You'd have to under clock it so low that it would not be worth it. Another issue is Dell's limiting the PCIe X16 slot to 35W.

I have that same Galaxy GTX 750 Ti card in a HTPC I just recently built. The case came with a 300W peak (270 sustained) PSU. I changed it out to a Seasonic 300W PSU with 2 x 18A +12V rails. http://www.newegg.com/Product/Product.aspx?Item=N82E16817151113

The original PSU only had 1 x 13A and 1 x 7A +12V rail. The PC kept re-booting when gaming at intense levels.
 

TonyD123

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I had a sneaking suspicion but thanks for confirming. So in essence, I would need a new PSU and likely a new MBoard which itself would be unlikely to fit in this case as it would not be proprietary Dell. Great. Also, assuming I keep using this MBoard (I know I know: I would be asking for trouble), does the fact that this PSU only have 1 12volt rail mean that I can't use PSUs with 2 rails? maybe it's a stupid question, but I would have thought that Dell do not include more sockets than necessary on their MBs

Also, that seasonic looks brilliant (though apparently somewhat noisy) but:
a) it has been discontinued; and
b) newegg.com doesn't ship to the UK, so I would have to find something similar (TFX) here, which I've read can be very difficult.

I got this PC as more or less a gift from a colleague who had managed to overload it with viruses such that it wouldn't boot, hence I am somewhat unwilling to gut the thing; I might as well build my own then.

I've read that Dell's 35W limit is really a non issue. I suppose the real question is am I prepared to find out though...
 

TonyD123

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Oh, also, there seems to be a 1GB version of the same card. I'm thinking that the 2gb may just be a marketing ploy, especially as my monitor only goes up to 1050 anyway. It retails at 85 GBP.
clutchc I also meant to thank you for your answer but forgot, so thanks!
I would like to know though, what do you consider intense gaming? because at this point I half a mind to buy and ATX 600W seasonic and leave it outside the case! =]
Cheers.
 

clutchc

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OK. A lot to digest there.
First, you may have the wrong idea of what we mean by the +12V "rail". That is the circuit, the +12V circuit... not to be confused with the gfx card slot if that was your meaning. You can use any PSU that fits your case. Do you know if it is a TFX, SFX, Mini ITX, Micro PS3, or a Dell proprietary PSU?

The 35W slot limitation would only be an issue if you were using a card that did not have an aux power cable to feed it. Sadly, that would be the case with the L-P Galaxy card. So I would avoid the card just for that reason alone. But if you have a link to a discussion of it neing a non-issue, please pass it on.
There are no low profile cards that I am aware of that require an aux 6 pin power connection. And all the cards that are 35W or less, are not suitable gaming cards at anything but the lowest resolutions.

Yes you are correct. At 1680x1050 resolution, 1GB is all that will ever be used on a card of the caliber that would fit in a L-P case. The more powerful cards can utilize more VRAM at higher resolutions (1920x1080+) and for more Anti Aliasing and greater textures.

Which of these 790 Optiplex is yours? http://media.engadget.com/img/product/32/oqp/optiplex-790-2kqe-800.jpg
 

TonyD123

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The second Optiplex from the left is mine.
And so I assume that 2GB would be a waste of money even if I wanted to play on my 1080p plasma (though I'm sure the 1gig would be sufficient, so... nevermind).

Now, as for the rating being a non-issue, I have read around (quite a bit) and have realised that people have 6600s (6670s if memory serves) and some even 7750s in the desktop and minitower version of this pic (though admittedly with a 265w PSU).
I will dig through history to look for the links, but I know there are some threads here and another on overclockers UK - one guy sawed off half of the heatsink on this card and put in a pc the size of a haribo pack.

The type of supply is either TFX or Dell proprietary but it is TFX 'shape' regardless.

oh! here is the pic:
s1.postimg.org/iblacgdxb/750ti.jpg

and the link to the same site:
http://forums.overclockers.co.uk/showthread.php?t=18590027

of course, his PSU is different, but I will endeavour to take a picture of my own PSU label tomorrow and post it here.
 

clutchc

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Will what fit? A Galaxy GTX 750 Ti? Mine measures 38.1 mm in thickness if that's what you mean. You have enough room for a 2-slot wide card because there is another slot next to the card if I'm seeing right. But air flow may be an issue if the card is too close to the PSU.

Can you locate an HD 7750 or R7-250 or even an GT 640 L-P card in your area? That is the next step down (in roughly that order) in performance from the 750/750 Ti.
 

TonyD123

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38.1mm will fit for sure. As for air flow, I think you're right.

Now as for the cards you suggested:
I saw a VTX3D 7750 available on amazon uk but it has since been remove from sale. The only thing left is a sapphire hd6670 (uses 60w anyway); HIS radeon hd 7750 (which I think is DDR3, priced as though it were DDR5 @ 100GBP, and the reviews I've read are generally of the opinion that this particular version of the hd7750 is substandard.

I did read about a LP r7 250 (an 8670 with a new sticker) but the prices,bizarrely, are close to the GTX 750 (not Ti).

The GT 640 uses 75w, or so I read.

Ultimately, I think I'm looking at using an external PSU despite my initial reservations. Is the PSU standard TFX or Dell prop by the way?
 

clutchc

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Looking at the PSU nameplate in one of your pics, I'd say it is a Dell proprietary since it has their name on it.

I've been re-thinking that 35W limitation on L-P Dell's PCIe x16 slots. I can't be sure, but I suspect that the slot itself and MB circuitry would be fine with providing the normal 75W for those slots. I imagine it might just be a limitation put on the PSU requirements for SFF and some HTPC PCs. By putting on a 35W limitation, they can get by with smaller PSUs for those tiny cases. Your finding other folks' statements supporting the slot being safe at 75W would seem to confirm that.

Using a new external PSU would be 'less than ideal' esthetically. But it would solve your problem. You could then remove the stock PSU completely and have plenty of room for the GTX 750 Ti. And I can vouch for the Galaxy 750Ti being a great gamer with a decent CPU. What is the CPU you have?
 

TonyD123

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Hahaha! I knew it had to be Dell trickery! I would have thought it highly unlikely that they would change the boards that much - I know that they have them custom'd from Intel but that would low even for Dell.

You're absolutely aesthetically it would look horrific, but hopefully I can compensate by getting a PCIe extension cable so that I can still use that second slot for a wireless card? (I would use the 2nd slot for the card but it's wired at x4 - another cost saving measure no doubt). If you know of such a device, do you think you could post a model no. or link (don't worry if you can't find a UK link, I'll use the model number or something).

Though I'm not yet completely decided on an external PSU, do you think that I can, or indeed should, underlock the card on the current PSU, if only temporarily until I get the new power supply?
I was thinking of getting a corsair 80+gold between 800w and 1000w; futureproof right? Even if I move to a new case or build a new machine (maybe even SLI - this card cant hardware sli but maybe software when the price drops) machine entirely?

The Dell CPU is i5 2400 @ 3.1 ghz I imagine with the fan I might even be able to clock it up, but one problem at a time eh?

Also, I've always wondered this: how easy would it be to transplant the ENTIRE contents to a full size emachines 8220 case (yh I know I know but it's one I have lying around and frankly I've run out of ways to repurpose a p4&geforce6200 AGP)

I must say though, thank you for all your help so far.
 

clutchc

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Check out this .PDF file http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CCcQFjAA&url=http%3A%2F%2Fwww.dell.com%2Fdownloads%2Fglobal%2Fproducts%2Foptix%2Fen%2Foptiplex-790-tech-guide.pdf&ei=q71vU_o6z5PIBMKxgeAL&usg=AFQjCNFUPhX2KkAjWxhGllsqdzjniN3vSg&sig2=cLSr7laR_AS4iMojA5YHjQ&bvm=bv.66330100,d.aWw
It should be the Dell manual for all 4 sizes of Optiplex 790 PCs; Desktop, Mini Tower, Small Form Factor, and Ultra SFF. I presume yours is the Small Form Factor.

I had to check out the motherboard layout of the SFF model. I just couldn't believe it had a PCIe X16 slot and another PCIe X16 slot @ X4 electrically right next to it. But it does! (scroll down to page 7 & 8 for the SFF). I have never seen that configuration before. Especially in that tight of a case. Almost useless. My suggestion would be to avoid the add-in wi-fi card and go with a good quality USB wi-fi instead. I (and others in my family) have had great success with this Wireless adapter in everything from Pcs to X Boxes: http://www.ebuyer.com/259799-tp-link-wireless-n150-usb-adapter-tl-wn722nc
It comes with a cradle and an 8' (2.4 meters) cable so you can position it for best signal strength if you are in a weak signal area. Or you can just plug the adapter itself right into the USB port on the PC.

Combined with the stock i5-2400 processor, the GTX 750 Ti will be able to play any game at mid - near max settings at 1080p... depending on the graphics level of the game. Crysis 3 plays at around medium settings for me with the old Phenom II X4 (3.7 GHZ) it is mated up with now. And Crysis 3 looks great at med settings.
The above rig has a W.E.I. score of 7.7 on graphics.

As to your question of down-clocking/down-volting the GTX 750 Ti temporarily to use it with the old PSU... it's worth a try. But I suspect it will have to be clocked quite low to avoid shutdowns during intense gaming. That old PSU's 17A +12V rail can't take too much. To your benefit, however, is the fact that you have a great Processor that only demands 95W at peak. That's ~8 amps at +12V, leaving you a whopping 9 amps for the Gfx card, fan(s), drive(s), MB.
 
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TonyD123

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Great. I've got a link for that wifi usb adapter from amazon uk and I'll get it once I've got everything else.

And as for the slots next to each other like that, well, it has a 5450 DMS-59 card now (single slot, rubbish cooler) so the other slot is presumably for an optional wifi card.

I've got a few exams (one tomorrow, the other in a week) but keep this topic open and I will repost to let you know what happens. I'll give you a best answer in the interim.

Does it make a difference if I get a fully modular PSU - it seems like it would be easier to plug everything in - I've read the manual and didn't get any indication that the MB is proprietary. I assume your reading of it indicated the same?

Thanks.
 

clutchc

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Yes, I would almost bet that is a Dll proprietary board. If you look under all the hardware in the way, you will probably see "Dell" silk screened in the middle. Here is a used one from ebay to explain what I mean: http://www.ebay.com/itm/Dell-OptiPlex-790-SFF-Small-Form-Factor-Socket-1155-Q65-Motherboard-D28YY-CVV31-/360932070417
I'm sure it was made by one of the major manufacturers (probably Foxconn), but it was made to Dell's specs.

There'd be no advantage to getting a modular for using it outside the case (other than less cable clutter). But a modular PSU will make it easier when it comes to building a new machine in the future, if that is still your plan. But you could save some money for now, by just getting a good quality 350W - 400W PSU instead. Here's a 350W Antec budget PSU that will do the job until you decide to build a new system:
http://www.amazon.co.uk/Antec-VP350P-350W-Power-Supply/dp/B00552K0IA/ref=sr_1_5?s=computers&ie=UTF8&qid=1399842582&sr=1-5&keywords=antec+350w+power+supply

And here's a review of it: http://www.hardwaresecrets.com/article/Antec-VP350-Power-Supply-Review/1500
 


A XFX 450W or Seasonic 420W PSU would also do well.
 

TonyD123

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That Antec is a brilliant short term solution and is probably the one I will get in the interim.
First though: I found these two by sheer luck this afternoon. What do you think? will they work? Admittedly I can't see the label so I will have to message the vendor but do you think these would work at least in principle? And finally is it just a case of taking the measurements on the current Dell PSU and comparing it to these supplies?
The storefront looks somewhat bare which is concerning but I defer to you as to how I would judge if the first PSU is really seasonic and not counterfeit.

#1
http://www.amazon.co.uk/Seasonic-SS-350TGM-Silent-modular-certification/dp/B009AFAAR4/ref=sr_1_5?ie=UTF8&qid=1399846759&sr=8-5&keywords=seasonic+ss

#2
http://www.amazon.co.uk/350W-Flex-power-supply-80plus/dp/B00J510QJK/ref=sr_1_15?ie=UTF8&qid=1399846759&sr=8-15&keywords=seasonic+ss

The latter has a label and claims 2 12v rails at 18amps each. I presume the former is the same.

I've already ordered the card by the way.
 

clutchc

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They are different sizes. The narrow one is a Flex ATX size and the Seasonic is a TFX size.
The Flex ATX size measures: 3.2" x 1.7" x 6"
The Seasonic TFX measures: 6.9" x 3.3" x 2.5"

Sorry, you'll have to do the metric conversion. Looking at the pics you posted of your PSU, I'd guess it was a Flex ATX.
Look on the end where it is screwed to the case. The hole pattern should look like this for the Flex ATX: http://upload.ecvv.com/upload/Product/20109/China2010927954058.jpg 3 or 4 holes in an L pattern.
The hole pattern for the TFX should look like this: http://images10.newegg.com/ProductImage/A3KX_1_20131117319993510.jpg 3 holes in triangle pattern.

What card did you decide on and order?
 

TonyD123

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Hehe, despite my better judgement I bought the 750 Ti with 2gig memory. I thought that since either way I will be getting a better PSU, I might as well overclock the card once I get the new supply and try to make full use of the 2gb. Is there anything that you would recommend that I do in order to realise the full potential of the extra gig? I assume increase the memory clock speed, use a higher resolution, that sort of thing?

I've read that using a twin rail (that is, two wired) PSU where there is initially a PSU with only a single rail can involve some rewiring of plugs, especially if there is not socket on the MB to put the second plug, do you think this will be a problem? Or is it just a case of pulling the PSU out now to verify the type off plugs required?

The card is arriving in about 2 hours but I won't have a chance to test it until tomorrow evening.

EDIT:
I've checked the dimensions for the current Dell PSU and it's not looking good:

http://www.amazon.com/originally-optiplex-fitting-physical-dimensions/forum/Fx2Y04J92N6IYRR/Tx1YYDTMFVRG8BR/1/ref=cm_cd_dp_aar_al_a?_encoding=UTF8&asin=B00CPPXKPK

To quote:
power supply Dimensions are 9 1/2" x 2 3/4" x 2 1/2"

The plugs appear to be different too. Curse Dell.


EDIT AGAIN:

These are the plugs for the seasonic:
http://www.hardocp.com/images/articles/1331767997TdfG13a5Kx_3_6_l.jpg

These are the plugs for the Dell:
http://www.redplanettrading.com/images/D/rv1c4-connections-800.JPG

As you can see, the 4pin plug is rectangular in the seasonic; square in the Dell. Presumably I will have to rewire? And there is a molex connector that I would imagine is the auxiliary 12v rail right?

I'm stuffed aren't I?
 

clutchc

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You're looking at the wrong plug on the Seasonic. That flat 4 pin is for older floppy drives. The Dell 4 pin CPU power connector is std. Every PSU has one of them. The pic you posted of the Seasonic cables just doesn't show it. (it may be the little white end barely in the left side of the pic)

But, yeah, the Dell PSU may be proprietary in physical size. I was afraid of that.
I thought you decide to go with a conventional PSU so you could have it for future building. And just wire it outside the case. You'll have to remove the Dell PSU anyway to use the dual slot GTX 750 Ti. Otherwise the fan will be choked for air intake sitting so close to the PSU.

You don't have to overclock the gfx card to utilize the 2GB VRAM. It will use as much as the the AAA settngs, the textures in-game, and the resolution of your display demand. That is the purpose of the 2GB of VRAM. OC'ing the card simply makes it run faster. And remember, it already has a small factory OC on it if you got the Galaxy.
 

TonyD123

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Regarding the graphics card, fine I will simply crank up the settings - great!

Now, for the PSU, you are correct I had decided to go external. But then I found the Flex, the Seasonic and another, albeit out of stock, from overclockers.
http://www.overclockers.co.uk/showproduct.php?prodid=SA-011-OP&emcs0=2&emcs1=Produktdetailseite&emcs2=CA-308-SV&emcs3=SA-011-OP
Hence why I have suddenly become interested in size. Ultimately, if the Flex can support my machine (by the way it is listed as flex but the label on the picture and the code it is listed under say seasonic) then I would love to offset building an entirely new machine (at least until I finish university) and have, for all intents and purposes, a small powerful and versatile gaming mini-pc.

I will check the 'Flex' again for that 4 pin, and indeed the other connectors. Tomorrow I will take a picture of the GTX 750 Ti in the slot and post here. I have a suspicion, but until I actually install it I won't know for sure if it fits properly.

I'll keep you posted.
 

clutchc

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Can you physically measure the length, width, height of the Dell PSU yourself to be sure the flex won't fit? Btw, not the one in your link. This one: http://www.amazon.co.uk/350W-Flex-power-supply-80plus/dp/B00J510QJK/ref=sr_1_2?ie=UTF8&qid=1400025909&sr=8-2&keywords=seasonic+flex+power+supply
I assume the Dell is indeed a proprietary, but it sure looks like a std. flex. Btw, 'flex' is a size designation, not a brand.

Either way, putting the GTX 750 Ti in the case with a PSU installed in there is going to be hazardous to the health of the card unless there is more room between card and PSU than I imagine. Looking forward to the pics.
 

clutchc

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Hi. Great pics. That is just about the space I was expecting you to have between PSU and card. I see you still have the Dell PSU installed. With the Dell PSU measuring more than 1.7" wide, it must be a proprietary design. A std. flex may not fit. And a TFX will be too big.

I just ran the default 1080p benchmark in Furmark. http://www.ozone3d.net/benchmarks/fur/ My Galaxy GTX 750 Ti reached 59C in that time. The card's heat sync was what I would describe as quite warm to the touch. At idle, the card's heat sync is cool or room temp.

Have you run the card in a game yet, or done any stress testing to see how the small PSU will hold up? I found this retailer selling PSUs for the Dell 790. I can't vouch for them, but I thought I'd pass it on. http://pointtek.ecrater.com/p/17380961/dell-optiplex-790-desktop-power-supply-450

 

TonyD123

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I've run some games with the case lid off but that is not a real indicator of the actual environment.

I ran the thief ingame benchmark on ultra and despite maxing out all 4 cpu cores and likely the graphics card too, it did not shut down. However, the benchmark is only 4 minutes long, and the lid was off, so I have ordered an LP bracket and will retest when it arrives.

Is it safe to assume that the power cutting out once or twice, say during testing, will not harm the components?

Also, johnnyguru reviewed the Flex and said that, with some load, it sounds like a screech (on account of the higher rpm required of the small fan I suppose) which isn't brilliant.

I was thinking of turning the flex on its side and using it like that, though that might cause some fan obstruction. Any thoughts?

Ultimately, I will just have to make cardboard mockups of the Flex and see if it will fit. Fitting horizontally leaves it just 1mm over the top of the case: some gentle force might push it in (unless my maths is WAY off base).

As for the company you mentioned, frankly I think having to RMA the PSU in the event of it being DOA will be painfull (back across the Atlantic!) I will use Furmark when I next get the chance. Well, the chance and the brackets.
 

clutchc

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Those bastards didn't send you any L-P brackets either? Same thing happened to me when I ordered it direct from Galaxy. After some correspondence back and forth, they happily agreed to send me the L-P brackets free. Now I see they are selling the card WITH the L-P brackets:
http://store.galaxytechus.com/GALAXY-GeForce-GTX-750-Ti-GC-Slim-2-GB-GDDR5-PCI-Express-30-DVIHDMIVGA-Graphics-CardbrbrBONUS-Low-profile-brackets-now-included-freebrbrFree-Gift-150-In-Game-for-Warface-Path-of-Exile-and-Heroes-of-Newerth_p_90.html
(of course, this was after I already found/bought some at Amazon.)

As to the PSU... If all that happens when the PSU gets over loaded, is that the +12V output drops below what the PC can run at, no harm will be done... it will either shut down or re-boot.
Of course, there's always the slight chance that the PSU will smoke itself with the possibly of taking something it's connected to out with it. Cheap PSUs tend to do that. I would expect Dell to use better units than that, though.
But to be honest, I never expected that single 17A +12v rail to allow gaming. What resolution were you gaming at, 1080p?
 

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