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5770 on a 400W generic PSU with 17A on 12V rail

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April 27, 2010 11:40:29 AM

Hi,

I don't want to spend anything more than 20$ on a PSU coz I already have my budget stretched with my heart set on 5770 HAWK edition.

My specs:
Intel Dual Core E2160
1 GB DDR2 RAM X 2
1 SATA 7200 RPM x 1
DVD RW drive x 1
iball 400W generic PSU with 17A listed on the 12v rail
MSI Radeon 5770 HAWK version x 1

I've researched and read many threads, and the most I can gather is that the PSU might be able to handle the card. I'm not able to find out if the 'iball' PSU is of good quality or not. I've heard conflicting reports about it. One of my friends is successfully running a 4870 ( much more power hungry than 5770 ) on it for a year, while I've heard it dieing out on modest 4xxx series from others.

I'm ready to risk my PSU, but just my PSU. Should I try to install the card and run it ?
a b U Graphics card
April 27, 2010 11:48:11 AM

Whats the age of the iball PSU? As budget PSUs age they loose the ability to output full rated power.
You're actually going to be risking your PSU, your video card and your motherboard. It's a system that works together and there is a risk it could die together.
April 27, 2010 12:00:05 PM

The PSU is 2+ years old..

Is there any other less power hungry card I could go for that will run most modern games with my Dual Core CPU at decent FPS. I won't be running at more than 1600 resolution or be using Eyefinity in the forseeable future.

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a b U Graphics card
April 27, 2010 12:19:24 PM

The main reason the MSI 5770 HAWK is so interesting is it's unlocked overclocking ability. Of course that's going to increase the demand for power.

An option you might want to look at is the MSI Dark Knight 5750 1GB video card. It looks like it used about 10% less power at load.
MSI Dark Knight 5750 1GB $120 after rebate
Of all the benchmarks I saw there wasn't any game playable on the 5770 that wasn't also playable on the 5750 - just a few less frames per second.

April 27, 2010 12:56:57 PM

I dropped the 5750 because its too near to the price to a 5770, which is too near to the price of the hawk edition. I plan to utilise the hawk's overclocking ability in the future when I'll be able to afford a better PSU. I plan to change the PSU along with the mobo and processor in the far future and would like to retain the GPU when I do that.
a b U Graphics card
April 27, 2010 1:09:40 PM

My advice is to take care of the power supply first. It's the limiting factor in your system right now.
April 27, 2010 1:26:24 PM

Thanks....can you suggest some good PSU for under 50bucks which will tide me over for 6 months?
a b U Graphics card
April 27, 2010 1:28:48 PM

You will be really pushing it on that PSU. I run a 5770 on an Antec Earthwatts 380w PSU, but that has 27A on the 12v rail. That should put it in perspective - your Iball could likely become a fIreBall! Best case scenario is it just won't work and will shut down under 3d graphics load, worst case it goes pop or bang and takes some other components with it. As WR2 says you really need a better PSU first.
You won't have to spend big money to get a better PSU, double your $20 and you will probably be able to pick up a new EA380w. You need something from a good brand with more than 25A combined output on the 12v rail(s).
a b U Graphics card
April 27, 2010 1:35:57 PM

Where will you be ordering from? It's easier for us to look over the options you have then make recommendations that aren't available to you.

Double check your iBall and make sure its 17A total. We've seen people that didn't realize some PSUs have 2x 17A rails. If in doubt, post a picture or just type the info from the PSU's data card.
a c 125 U Graphics card
April 27, 2010 2:27:27 PM

A mistake many people make when trying to find out the total amperage on the +12V rail(s) is to simply add the rails together, for example: A PSU may have 2 rails at 19A each, but that doesn't mean to say that both rails can provide 19A at the same time for a total of 38A.

The way to find out the max amperage your +12V rail(s) can provide is to look at the sticker on the side of the PSU and look at how many watts is dedicated to the 12V rail(s) then divide that number by 12 to give the Amperage

For example: A 700W PSU may have 650W dedicated to the +12V rail(s), so you divide 650 by 12 to get 54A
a c 140 U Graphics card
April 27, 2010 3:20:26 PM

As everyone is discussing your PSU is a little on the, not so good side for a more powerful dedicated graphics card. 400W is usually perfectly fine for a 5770, however the single 17A rails kind of worried me. More halfway decent psu's would have (2) 17A rails, and I am guessing this is more of an OEM type PSU. 17A * 12V would only give you 204W for 12V which isn't all that terribly much. The 5770 has a max power usage of 108w, which would be 9A. Granted it will probably never use this much, but you should plan with those numbers. Your CPU and system wouldn't really consume that much power, but I have a feeling that PSU isn't all that efficient either. It is always best to be on the safe side, and a PSU is never something you want to cheap out on. If your PSU is overloaded or fails it can take out more than just the PSU. It has the potential to take out anything plugged into it. So having a good quality unit is usually something worth investing in.

The Corsair 400W is really a solid PSU and I highly recommend it for an application like this. It' has 30A on the 12V rails and is a trusted and true unit. $55 - $10MIR and free shipping.
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
There are other units that I could recommend, but most are over the $50 mark and sometimes have MIR's so if you are with waiting for a check I could suggest a few. I always like having more than I need in the PSU because they can last you a few systems and be used over and over. Also, look for combo deals on Newegg. They often have PSU and video card deals that sometimes are very appealing. And also watch for free shipping as it can save you some money. http://www.newegg.com/Store/ComboDeals.aspx?ComboStoreI...

April 27, 2010 5:31:26 PM

Thanks everyone....
I've now decided to drop the idea of experimenting with my current PSU, and am now actively pursuing a cheap PSU.

@WR2: I live in India, and for comparitive prices you can check out ebay.in . I won't like to spend more than Rs.1500 (~$34) on a new PSU. And I've checked again and its only 17A single rail. And from what I've been able to gather in the last few hours, i would be lucky if its giving 10A even.

@Omgits: Thanks for the caution. It was already on the back of my mind but its nice to be reminded before I make a purchase.

@jay2: I really can't afford a crosair PSU. the one you mentioned is around 100$ here.

All I need now is info on which PSU to get. As I can't afford quality ones like crosair or cooler master, I'm going for local manufacturers. Can someone please suggest me what should be the Amps on all the rails ( and how many rails should be there) for my rig to work.
April 27, 2010 5:55:14 PM

Also, I've opened another thread looking to see if I can't get a good gfx card which will work on my existing PSU. I'd only be requiring resolutions of 1400x900 max, and am not ever going to use eyefinity or crossfire. But I'd like the card to be able to play every game (albeit at a lower setting ) coming out for at least a year.
a c 125 U Graphics card
April 27, 2010 5:55:20 PM

25A should be enough, and I would go for a single rail PSU

I'd highly recommend you save up until you can afford a quality PSU. Buying a generic PSU could kill your other components.
April 27, 2010 6:04:51 PM

Rustyy117 said:
25A should be enough, and I would go for a single rail PSU

I'd highly recommend you save up until you can afford a quality PSU. Buying a generic PSU could kill your other components.



So 25A listed should be enough or the actual output should be 25A ? As I said I'm looking to buy a generic one to tide me over for a few months. Then I plan to upgrade the mobo, cpu and PSU (if required). Since I will calculate that the generic ones will be at 50% efficiency, so should I go for the one which lists 50A on the 12v rail ?
a b U Graphics card
April 27, 2010 6:20:09 PM

jekyl87 said:
The PSU is 2+ years old..

Is there any other less power hungry card I could go for that will run most modern games with my Dual Core CPU at decent FPS. I won't be running at more than 1600 resolution or be using Eyefinity in the forseeable future.


In your other thread on this same topic, you mention not going higher than 144x900 or 1280. Why are you creating multiple topics on the same subject, and then changing your information?

jekyl87 said:
Also, I've opened another thread looking to see if I can't get a good gfx card which will work on my existing PSU. I'd only be requiring resolutions of 1400x900 max, and am not ever going to use eyefinity or crossfire. But I'd like the card to be able to play every game (albeit at a lower setting ) coming out for at least a year.


Ahh, there's my answer.

As I mentioned in your other thread, I think there's more to consider than just your PSU. Your system could benefit from more RAM at the least. And quite frankly, the CPU is aging a bit as well. Guess it depends on what "modern" games you actually intend to play.
a c 125 U Graphics card
April 27, 2010 6:24:57 PM

No I'm pretty sure it works like this, say your PC requires 100W and your PSU is 80% efficient that means the PSU will have to draw 120W from the wall to be able to provide enough power to your PC.

The higher the efficiency of the PSU the less energy is wasted, so in turn a more efficient PSU can save you money in the long run, which is another reason to get a quality PSU

Say your right and a generic PSU you get is 50% efficient (which is terrible) and your PC needs 400W, the PSU will pull 800W from the wall and half of that will be wasted and half will be used by your PC

And i mean 25A on the 12V rail alone.
a b U Graphics card
April 27, 2010 6:29:17 PM

jekyl87 said:
Since I will calculate that the generic ones will be at 50% efficiency , so should I go for the one which lists 50A on the 12v rail ?
Not necessary to make that efficiency calculation. That only applies to the input power from the wall socket. As in for a 75% efficient PSU to make 400W of power it will need to draw 500W from the wall socket to make that 400W of DC power.
If a PSU is rated for 400W and 25A +12V that is the DC power it can deliver to the PC components.
It's not quite that simple, but its a good rule of thumb.

Here is the data plate of a budget $30 PSU I could buy. COOLER MASTER Elite 460 RS-460-PSAR-J3 460W



It says 460watts and 2x 18A +12v rails. But if you look closer it shows the 2x +12V total output is 324W or 27A
And if you look real close at the fine print it says the total output of the +3.3V, +5V and +12V shall not exceed 377.9W

I could not find any PSU in your price range I can recommend. The units in your price range did not provide enough details to avoid the kind of gotcha's in the PSU above that takes a '460W PSU' and gives you something a lot less.

If you want to copy the details of the data plates of PSUs you're looking at we can help you decide which ones are the best option.


April 28, 2010 4:52:55 AM

@je : My mistake. My monitor can handle 1440x900 and I don't intend to buy a new monitor anytime soon.

@omg, WR2: Thanks. This cleared up things a lot. Now finally I've decided to buy a 5750, and put the money saved towards a corsair 400W psu. And maybe if I have some left over I'll put it in the savings to upgrade the mobo and the cpu down the line.
a b U Graphics card
April 28, 2010 5:07:43 AM

I think that's a smart move. Sure the 5770 is faster, and a sweet card.
But there won't be any game that the 5770 can play that the 5750 can't also play.
And a good stable PSU is protection for your system and piece of mind for you.
a c 125 U Graphics card
April 28, 2010 11:19:20 AM

Good choice jekyl87 :) 
May 3, 2010 6:03:11 PM

Ah correction on my above post. Have already bought a sapphire 5750. Tried against my good sense to run it on my existing PSU. The card didn't start (even the fan on it didn't move). Now planning to buy a generic 600w PSU (named Atek) for INR800 (~$17). I'm doing this coz
I've learnt that 99 time out of 100, the PSU shorts out leaving the other components intact. Since the only thing of value i have on my rig right now is my new card, i'm not so worried about the cheap psu and other components. And yes, I know that even if it runs, it will seriously hamper the life of my card and other componenets, but I really can't afford anything more right now. The corsair 400 is above 3000INR here. Will post again if it works.
a b U Graphics card
May 3, 2010 6:16:14 PM

jekyl87 said:
Ah correction on my above post. Have already bought a sapphire 5750. Tried against my good sense to run it on my existing PSU. The card didn't start (even the fan on it didn't move). Now planning to buy a generic 600w PSU (named Atek) for INR800 (~$17). I'm doing this coz
I've learnt that 99 time out of 100, the PSU shorts out leaving the other components intact. Since the only thing of value i have on my rig right now is my new card, i'm not so worried about the cheap psu and other components. And yes, I know that even if it runs, it will seriously hamper the life of my card and other componenets, but I really can't afford anything more right now. The corsair 400 is above 3000INR here. Will post again if it works.


I would still get a better powersupply and the Atek if you can....
!