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2x8800 GT in SLI + overclock for 1?!?

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February 4, 2013 8:57:54 PM

Hi!
First I'd like to say hello to everyone reading this post (and others as well, but they will, sadly, never get this message ;)  ), I've stumbled on your excellent articles and forum discussions numerous times and was always able to get the answers I needed (until now, that is), for which I would like to thank you from the bottom of my heart!

So here's what I wanted to ask, because I was unable to find a closely related theme (if it exists and someone gives me the link, I'll gladly read it...) :
I have been playing around with an idea of upgrading my semi-old computer a bit and came to this system:
Gigabyte GA-EP35-DS4
Intel Core2Quad Q9400 w/ Arctic Freezer 13 CO (not OCed yet...)
2x 2GB + 2x 1GB PC2-6400 Patriot RAM (kinda shabby, I know, but it works for now)
2x Nvidia GeForce 8800 GT 512MB (1x Inno3D default clock w/ Zalman VF1050 and 1x BFG OC2 version w/ Zalman VF900-Cu)
2x HDD + 1x SSD
XFX PRO650W PSU
Win7 64bit Professional

I have not yet installed the second 8800 (have tested it out though), because I read that both cards need to be clocked the same (not sure if only core or everything), before I can attempt SLI. My question is therefore whether I can get my card to work in SLI with the new one (BFG) if I OC it to the same clocks? Or maybe underclock the BFG?
I have another problem though. My MOBO isn't designed for SLI support but only for CrossFire. I have read that some MOBOs like that just plain work with SLI cards installed or I may need to use a software solution like HyperSLI. Does anyone have experience with that specific model (again, haven't been able to find any info on it)?

I have another option, but one I'd rather not use: I could get my hands on another BFG OC2, but it'll cost me 40 €, and I've already spent about as much money on my upgrades as I was hoping to. Also, if it turns out my MOBO doesn't work with SLI, I'm looking at finding a socket 775 SLI MOBO, which are as rare as a 90 y/o's teeth... Not to mention expensive.

Oh, and another little thing: if I understand the GPU OCing correctly, I need to run the program with which I OCed the card ALL the time after I do it? Or do the settings get saved to the card (it's BIOS or whatever it may be called)?

Thanks in advance to all those who are going to be willing to help me tackle these problems of mine! :D 

More about : 2x8800 sli overclock

a b K Overclocking
February 5, 2013 8:29:33 AM

You should be able to oc or underclock one of the cards and if done correctly they should work together in an sli setup. Your overclock settings will not be permanent, you will have to run the program every time (or have it automatically start with windows)

You can flash your oc settings to the bios of your graphics cards. This would be a permanent solution and a pretty stable and reliable one as long as the settings are good and stable. However, flashing the cards bios is dangerous and can brick your card. It also voids your warranty. It is more suitable for the more advanced risk taking users.

You can force/spoof a non sli board to work with an sli setup... but thats not guaranteed and the only way to know is to try and see. Trial and error is sometimes your best friend.

PS: You can actually find some pretty good 775 boards for ok deals on ebay... just gotta look out for them ;) 
February 5, 2013 11:23:30 AM

Thanks for the answers!

Is there any way of knowing if my OC is the reason for SLI not working, when I actually go for it (I fear there isn't)? I'll have 2 variables here (the OC and the board issue) and it would be great to be able to distinguish between them :)  .

I will definitely look into flashing the bios (warranty is loooooong gone anyhow), I've successfully done it for mobos a couple of times, this shouldn't be that much harder (I hope?).

As for ebay deals, which ebay are you talking about and for what kind of money? I've been looking around a bit: on ebay.de the offers start at about 80 €, on ebay.co.uk I've seen one for £59.95 and most are not available for shipping to Slovenia, where I'm from :/  Some are up for bidding and I honestly have no idea how high those go.
P.S.: I just found a local offer for an Asus P5N-D right in my home city for 50 €! That's affordable, so I really need to get to OCing and testing my stuff, so I can see whether I can get by with my stuff or need to buy this one :p 
Related resources
a c 105 U Graphics card
a b K Overclocking
February 5, 2013 1:06:24 PM

what's the monitor/resolution?

anyways, If you want an upgrade, forget the sli and the xfire and just but a single better card.
February 5, 2013 2:18:08 PM

I currently have an LG L194WT @1440x900 (will be getting a larger one in the near future).
Also, this upgrade was actually a little project, a hobby of sorts :)  so I'm going to go with what I have. I'll leave the better, new card for when I can save up the kind of money to build a new machine...
a c 135 U Graphics card
a b K Overclocking
February 5, 2013 2:28:36 PM

I use to run a pair of XFX 8800gt's one was factory oc'd and the other wasn't I didnt need to underclock or overclock to get them to work in SLI.
a c 135 U Graphics card
a b K Overclocking
February 5, 2013 2:32:30 PM

SLI only requires that they use the same gpu, having the same clock speeds in not required. My current setup I have 3 GTX 580's 2 are from the same manufacture and have the same clock speeds, the 3rd is from a different manufacture and has different clock speeds and they work just fine together in SLI.
a b K Overclocking
February 5, 2013 8:04:44 PM

@bignastyid you're probably right...

Sli shouldn't require same clock speeds. I just wasn't 100% sure how sli behaved back in 8800 days. I know sli was a bit picky back then.

I had a crossfire setup and that didn't require the same clock speeds. In fact, I had 2 different 4850 cards, one from sapphire and one from asus. Both were clocked differently but ran crossfire very well.

swifty_morgan is right, you would probably be better off with a single newer better card. However, if you already have 8800s then you're not loosing anything trying to set up that sli.

In fact trying to get the sli to work would be the cheapest way to improve your current system. All it will cost is time and effort.
a b K Overclocking
February 5, 2013 8:17:11 PM

@IdijotSLO

Flashing nvidia cards is not too hard. though you would have to do it through a bootable disk in command line format. I have flashed many nvidia cards bioses successfully and never had issues with them. I have also flashed many ati/amd cards and they work well too... but I have had 1 or 2 cards get bricked before. I have never bricked an nvidia... they seems to be a bit more brick-proof than ati/amd because if you brick an nvidia you can reflash it back to stock bios successfully. You can do that on ati/amd too but sometimes the cards bios gets corrupted badly and doesn't identify as an ati/amd card...the flashing utility won't reflash it because it looks for an ati/amd card and will not proceed to flash if it doesn't see one. But nvidia can be force flashed back even if the card doesn't identify itself.

The reason I told you this is because if you find good oc settings for your cards, ones that are stable, you can flash them to the bios so they stay that way. Even if you reinstall windows your oc settings will stay. That way yhou can squeeze more performance out of your cards in addition to sli (if you get that working)

Start messing with your stuff and keep us posted. If you need help I'm sure we can help ;) 
February 5, 2013 8:26:37 PM

Here is all the info you need to know:
http://www.geforce.com/hardware/technology/sli/faq#c18

I honestly wouldn't advice on spending anything more to upgrade your current system but instead save for your next upgrade, my system is almost like yours and though it works rather well it does shows its age for some things.
February 5, 2013 11:28:31 PM

Thanks for all the replies, you guys are really awesome :D 

So, for now, I've successfully OCed my second card... Or so I thought :/  I tested it out with MSI Kombustor for a bit, didn't get any high temperatures (below 60° C at all times) and no artifacts, have to admit, I wasn't really patient, as I thought I'd test it later with Crysis. I also kind of got ahead of myself in wanting to get my SLI up and running, at which I succeeded with the use of HyperSLI.
Happy about it, I set out to test it in-game. Settings on High, I didn't get really high FPS, I suppose 35 on average. And after about 50 min... artifacts :( 
That got me to thinking and I ran Kombustor again, this time with SLI active. The first thing that stroke me as odd was that only 1 GPU was doing all the work during the test?!? I also ran a OpenGL 2 GPU burn-in test for about 15 min, which got the active GPU to 84° C (it settled there with no artifacts at that time, but the card doing all the work was the factory OCed one anyhow).
So I did some reading and found that even though the usual stress tests only use 1 GPU, Crysis should be using both cards. Which got me thinking even further. And also checking things. Turns out my MOBO only has PCI-E x4 on the 2nd slot and not x8, as I thought :ouch:  (I read somewhere that the difference between 2 x16 and 8+16 was less than 5 %, so I never worried). BIIIIG mess up on my side. I think that those artifacts may be a result of this too... I'll try running each card separately and see if those artifacts come back with either one, and then underclock accordingly.

So it comes down to this: I wasn't planning on putting together a new computer for at least a year or even a bit longer, hence I want to make do with what I have and maybe just a bit more. It seems to me that I'm going to have to go for that MOBO I mentioned in the 1st post. If I can't get it, I'll have to do some serious thinking and/or gold-digging :kaola: 
February 6, 2013 12:09:37 AM

Did you enable SLI on the Nvidia control panel? If I remember well there are some options there that can turn your secondary card as a physx card if not configured properly.

Also, some games work well with SLI and some not, don't expect twice the performance in all games. If your cards are artifacting due to unstable overclock then set both cards to match a default clock rate. Lets say one card is running at 600mhz while the other at 650mhz, set the second card to 600mhz instead so you at least know the system will be stable.
February 6, 2013 8:46:08 AM

SLI was enabled, but as I mentioned: my secondary PCI-E bus only supports x4, so it is probably heavily bottle-necking the SLI performance.
Would there really be any point in trying to test the SLI under these circumstances?
a b U Graphics card
a c 225 K Overclocking
February 6, 2013 9:38:16 AM

You're attempting to run SLI on a Crossfire dedicated motherboard.

With SLI sometimes being a touchy situation just changing from one driver to another on an SLI dedicated motherboard, you're attempting to run SLI on a motherboard not factory designed to even run SLI.

Rethinking this might be a good option.
a c 105 U Graphics card
a b K Overclocking
February 6, 2013 9:41:10 AM

single better card sounds better all the time...........

anyways, enable the second card to perform physx tasks. only option left.
a b U Graphics card
a c 225 K Overclocking
February 6, 2013 9:56:04 AM

swifty_morgan said:
single better card sounds better all the time...........

anyways, enable the second card to perform physx tasks. only option left.


Totally Agree! :) 
a b U Graphics card
a c 225 K Overclocking
February 6, 2013 10:05:41 AM

IdijotSLO said:
Gigabyte GA-EP35-DS4
Intel Core2Quad Q9400 w/ Arctic Freezer 13 CO (not OCed yet...)
2x 2GB + 2x 1GB PC2-6400 Patriot RAM (kinda shabby, I know, but it works for now)


You're by far not out of options do you intend overclocking the CPU regarding this setup?

It may be a Crossfire dedicated motherboard but was also a good CPU overclocker, you seemed to only be concerned with 8800GT overclocking and SLI options?

What are your intentions?
February 6, 2013 11:22:26 AM

I do plan to OC the CPU. Now the options I have seem to be as they follow:

1. I keep the stuff I have, use the 2nd 8800 for PhysX (no direct benefit to graphics there) and OC the CPU on this board, which is great for OCing.

2. I get an Asus P5N-D board (going to cost me 50 €), which will allow me to utilize both 8800s in SLI, but can be a bit difficult for CPU OCing, as I've read around the forums.

I'm not a really hardcore gamer, the only games I play regularly are Team Fortress 2 (which I run with a custom config, so my FPS don't drop too much; it is a more CPU demanding game though, I've heard) and StarCraft II (don't really know which option it would benefit more from). I was planning on revisiting some of the CODs with SLI, which I played before on really low settings so they were playable.
Any thoughts on that? :) 
a b U Graphics card
a c 225 K Overclocking
February 6, 2013 11:43:34 AM

Option 2 will allow for SLI and that will definitely benefit your gaming intentions, and you may get further overclocking the CPU than you think, if you can find one?
a b K Overclocking
February 6, 2013 5:05:57 PM

Yes, I would agree with Ryan here. On the contrary of what you have read about the overclocking abilities of the p5n-d, that board is actually on ok overclocker. I have had a p5n-e sli which is similar when it comes to ocing. I had a e8400 that I overclocked to 3.6Ghz without much work at all. It was 100% stable. I didn't try to go hight but maybe I could have squeezed more Ghz out of it... who knows? lol

Option 2 seems like a good option. SLI + an ok overclock and you have a system that should handle most games better.

PS: I don't have that 775 system anymore... kinda miss it... kinda don't lol...
I still have my phenom rig, my zambezi 8150 (bulldozer) rig, my i7 980x rig,
and I'm building a second i7 980 rig at the moment... fun stuff lol ;) 
February 7, 2013 8:40:45 AM

After hearing those words of encouragement (I was really skeptical about OCing on that board), I'll be ordering that mobo right away. I was hoping I could get my CPU up to about 3,2-3,6 GHz, I believe my cooler should handle that.
Can't wait to get to it! :D 
a b U Graphics card
a c 225 K Overclocking
February 7, 2013 9:08:43 AM

videl said:
Yes, I would agree with Ryan here. On the contrary of what you have read about the overclocking abilities of the p5n-d, that board is actually on ok overclocker. I have had a p5n-e sli which is similar when it comes to ocing. I had a e8400 that I overclocked to 3.6Ghz without much work at all. It was 100% stable. I didn't try to go hight but maybe I could have squeezed more Ghz out of it... who knows? lol

Option 2 seems like a good option. SLI + an ok overclock and you have a system that should handle most games better.

PS: I don't have that 775 system anymore... kinda miss it... kinda don't lol...
I still have my phenom rig, my zambezi 8150 (bulldozer) rig, my i7 980x rig,
and I'm building a second i7 980 rig at the moment... fun stuff lol ;) 


We've gotten spoiled by the ease of overclocking that's available today compared to the 775 days.

Looking back the 775 platform was a great overclocking adventure, and a lot was learned, but the convenience and simplicity of CPUs today tends to spoil us all. :) 
a b K Overclocking
February 8, 2013 5:53:42 AM

@IdijotSLO

Glad to hear you have a nice plan. Once you get the mobo and start ocing, post back on how the challenge goes. If you run into anything I'd be glad to help! ;) 

@Ryan, you're absolutely right... they were pretty tough at times and needed patience to get to good clocks. I remember I had a pretty surprising overclock on a board I didn't expect to get much from. It was a foxconn p35a I think.. I overclocked a pentium dual core (e5200 I think) to 3.8Ghz stable... that one took some time and patience lol but in the end performed better than a stock clocked e8400. Fun days lol :) 

PS: personal update, I got the second 6-core system done today. The formula surprised me with a pretty decent overclock... I got the 980 to 4.2Ghz stable. The 980x in my G1 Assasin probably overclocks better but it was definitely more bucks... so I'm happy with the price to performance ratio I got on this second 6-core beast. I do video rendering... thats what I need these beasts for.

PPS: Today I found out that a nicely overclocked 560 ti gets close to stock performance of a 580... a good way to save some money ;)  lol
a b U Graphics card
a c 225 K Overclocking
February 8, 2013 11:05:24 AM

videl said:
@Ryan, you're absolutely right... they were pretty tough at times and needed patience to get to good clocks. I remember I had a pretty surprising overclock on a board I didn't expect to get much from. It was a foxconn p35a I think.. I overclocked a pentium dual core (e5200 I think) to 3.8Ghz stable... that one took some time and patience lol but in the end performed better than a stock clocked e8400. Fun days lol :) 


I achieved 4.0ghz rock solid stable on my Q9550 using an ASUS Striker II Extreme motherboard, with 2,000mhz memory, cooled with a Xigmatek HDT-S1283 air cooler w 2 110cfm fans in push/pull.

ArthurH achieved 4.25ghz CPU-Z Validation (which I think is still in his sig), on his Q9550 using the same motherboard and memory, with Ice Chilled Water Cooling.

As far as overclocking is concerned I am most proud of that achievement, and I can definitely say it was a long and laborious achievement, but so very gratifying!
February 12, 2013 6:25:59 PM

I've been looking around for a mobo these last couple of days and found these, that I could potentially get my hands on (potentially being the key word, as not all are being sold separately and I don't know if I'll be able to persuade the people selling them to sell the mobos alone):
1. ASUS P5N-E SLI (http://www.asus.com/Motherboard/P5NE_SLI/#specification...)
2. ASUS P5N32-E SLI (http://www.asus.com/Motherboard/P5N32E_SLI/#specificati...)
3. ASUS P5Q Deluxe (http://www.asus.com/Motherboard/P5Q_Deluxe/#specificati...)
4. ASUS P5E Deluxe (http://www.asus.com/Motherboard/P5E_Deluxe/#specificati...)
5. GIGABYTE GA-EP45C-DS3R (http://www.gigabyte.com/products/product-page.aspx?pid=...)

If any of you guys have any insight into SLI and/or OCing with these mobos, I'd greatly appreciate it.

My thoughts so far are:
1. is not really what I'm looking for, as it only supports up to 800 MHz for memory and 8+8 in SLI. I'm thinking I should scratch that one off the list.
2. pretty cool mobo, only negative side is the 800 MHz limit for the memory (this may hinder my OCing of the CPU, if I understand things correctly - on the other side, I may not understand it correctly, as I haven't really studied OCing as much as I want to before I start... :whistle:  )
3. all around nice mobo, if I get the PCIE descriptions it works in 16+8, which is OK, but doesn't support SLI natively, which hopefully can be achieved painlessly with HyperSLI.
4. similar to 3. but with 16+16, which is better (but only by 5 % if a random internet tester can be trusted ;) )
5. much like 3. (the same chipset too: Intel P45 + ICH10R)

P.S.: Oh, and the ASUS P5N-D buy I thought was a sure deal seems to have fallen through, no response from the seller after I asked to buy it. :(  Still, it too had that 800 MHz memory limit.
!