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Is my PSU suitable for Crossfire?

geon106

geon106

geon106

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Joined
23 Dec 2010
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415
Location
Newcastle, Staffordshire
I'm thinking of doubling up my 5870 with another considering can now pick one up from OCUK for around £180. However my PSU may not be up for the job

It is a Jeantech Storm 700W modular PSU. Triple 12V rail. 4 pin CPU connector +additional EPS 4-pin for newer CPUs such as 2500k which im getting. Plus 2x 6-pin PCI-e cables with 8-pin adapters.

The 5870 has 2 power inputs, so i'm using both cables. If i add another i'm not going to be able to power it. I've been told you can get molex to PCi-E adapters but i've never liked using these power leads. Is my PSU going to be able to support crossfire with 2x 5870's?
 
I have tried to power up a pair of 5870 with a Corsair 650W PSU, using two molex-to-PCIE adapters for one of the cards. Didn't meet any problem.

However I hate 5870 1GB CrossfireX pretty much because while I had the GPU power I could not enable high AA in many games due to vram limitation. Most annoyingly, Crysis Warhead stuttering, Metro 2033 unplayable, WOW dual-instance unplayable. Thus if you play at 1680x1050 it could be a decent choice, however if you play at 1920x1200 I'd say think twice before you go for it.

By the way, £180 doesn't seem a very good price.
 
harmony said:
I have tried to power up a pair of 5870 with a Corsair 650W PSU, using two molex-to-PCIE adapters for one of the cards. Didn't meet any problem.

However I hate 5870 1GB CrossfireX pretty much because while I had the GPU power I could not enable high AA in many games due to vram limitation. Most annoyingly, Crysis Warhead stuttering, Metro 2033 unplayable, WOW dual-instance unplayable. Thus if you play at 1680x1050 it could be a decent choice, however if you play at 1920x1200 I'd say think twice before you go for it.

By the way, £180 doesn't seem a very good price.
Click to expand...

So even though you have combined 2GB of VRAM some games won't let you use AA?
 
Ignore harmony, at 1920x1200 a 5870CF will perform at the same level as 6870 CF.

/thread.
 
geon106 said:
So really there isn't any benefit in crossfire with 2x 5870s?
Click to expand...

You still receive benefit from adding another 5870, however the gain would be limited by vram, making me feel the £180 not fully utilized. I would wait for the upcoming 28nm cards if I can manage to hold with the upgrade itch.

See vram usage at 1920x1200 yourself: link
 
Really then my £180 is best put towards a better single card? Hmm, well tbh it saves me some money. My PSU seems perfectly fine to move from a Athlon 6000+ single 5870 and should be okay to go to a i5 2500k and a single higher card rather than 2x 5870's

Not sure what card i'll get though, from your thread i'll proberbly go for a 6xxx series 2GB card
 
geon106 said:
Really then my £180 is best put towards a better single card? Hmm, well tbh it saves me some money. My PSU seems perfectly fine to move from a Athlon 6000+ single 5870 and should be okay to go to a i5 2500k and a single higher card rather than 2x 5870's

Not sure what card i'll get though, from your thread i'll proberbly go for a 6xxx series 2GB card
Click to expand...

If you move from a single 5870 1GB to a single 6950 2GB, to be honest you wouldn't notice improvement in most cases, because a single 6950 (while having about the same GPU power as a 5870) does not have sufficient GPU power to enable high AA under high resolution to utilize more than 1GB while maintaining a decent framerate in games.

You only gain significant improvement by upgrading from a single 5870 1GB (or from a single 6950 2GB) to 6950 2GB x 2 CrossfireX.
 
harmony said:
If you move from a single 5870 1GB to a single 6950 2GB, to be honest you wouldn't notice improvement in most cases, because a single 6950 (while having about the same GPU power as a 5870) does not have sufficient GPU power to enable high AA under high resolution to utilize more than 1GB while maintaining a decent framerate in games.

You only gain significant improvement by upgrading from a single 5870 1GB (or from a single 6950 2GB) to 6950 2GB x 2 CrossfireX.
Click to expand...

How much of an improvement from a 5870 to a 6970 2GB? I noticed OcUK had one for about £250 or something reasonable. Would that offer a better performance increase?
 
Don't quote me on this but not much, you'll be able to use somewhat more AA for the same FPS.

I'd either try and find a second hand 5870 for <£120 or hold off upgrading til the 7xxx series come about. The 5870 is still a stonking card
 
d_brennen said:
Don't quote me on this but not much, you'll be able to use somewhat more AA for the same FPS.

I'd either try and find a second hand 5870 for <£120 or hold off upgrading til the 7xxx series come about. The 5870 is still a stonking card
Click to expand...

I've not long had the 5870, upgraded from an 8800GTX. I've yet to really judge it though as running a AMD Athlon X2 6000+ on 4GB 667Mhz DDR2 RAM

Once next week i get my i5 2500k, 8GB 1600Mhz DDR3 RAM and an Agility 3 60GB SSD the graphics card wont be bottlenecked.

I just wanted another card because the motherboard i'm getting is crossfire ready, so i figure for the extra money to potential get an additional 30-40% power may be a good idea. No i'm thinking save up over the coming months for a high end 7 series, like a 7970 4GB ~drools~ :D
 
From experience crossfire 5870 had it's benefits and the raw GPU power is fairly impressive. However if you're unlucky like me with drivers then it maybe more of a hassle than anything else.

When I ran crossfire 5870's, crysis warhead was stuttery and got texture flickering. The same happened in Bad Company 2 and also in shogun 2 and gta 4. It ran perfect in benchmarks like 3DMark11 etc.

I tried multiple drivers and when I got the drivers to work ingame, it would fail on me while on desktop getting te annoying 99% gpu load bug.

I sold both gpu's and got myself a GTX 570 today and it's performing great! Then again so was the 5870 when run on it's own.
 
geon106 said:
I've not long had the 5870, upgraded from an 8800GTX. I've yet to really judge it though as running a AMD Athlon X2 6000+ on 4GB 667Mhz DDR2 RAM

Once next week i get my i5 2500k, 8GB 1600Mhz DDR3 RAM and an Agility 3 60GB SSD the graphics card wont be bottlenecked.

I just wanted another card because the motherboard i'm getting is crossfire ready, so i figure for the extra money to potential get an additional 30-40% power may be a good idea. No i'm thinking save up over the coming months for a high end 7 series, like a 7970 4GB ~drools~ :D
Click to expand...
To be honest your current system would be bottlenecking your 5870 quite a bit. Once you upgraded to i5 2500K, you should see HUGE improvement on frame rates in game (probably double), and your 5870 should be more than sufficient to last you till the next gen card's arrival, so you can consider upgrading the graphic card then instead of right now.
 
Regardless of whether CF is worth it for you (I have no experience of running 5870 CF so can't help you), that PSU isn't great. Jeantech are a budget brand and I'd be looking at swapping it out for something decent ASAP. Generally, if you're paying roughly £1 per 10W it's decent.
 
Put it this way, my corsair HX650 barely ran 5870 crossfire. As soon as I tried to overclock anything my system would become highly unstable. And since your psu is a budget brand, I wouldnt chance incase you damage other components in your rig.
 
I have an ocz 700w with similar specs. It's stable with an i7 at 4.2 and two 5870s.

I don't agree with the VRAM argument. Yet to run into any issues with VRAM at 1080p. But then I prefer to get as close as possible to 60fps than to max out the AA. But metro 2033 and crysis 2 were doing 1080p and 4x AA just fine - the fps took a hit but it wasn't vram thrashing.

My only advice here is to go second hand, it's not an upgrade worth £180. Ifyou have that to spend your best bet by far is to sell your 5870 for 130-150 on an auction side, add the money to your budget, find another 30 quid from somewhere and buy a gtx580. Second hand 5870s on here, however, go for 120 which is a worthwhile spend in my book.
 
Ste said:
I have an ocz 700w with similar specs. It's stable with an i7 at 4.2 and two 5870s.

I don't agree with the VRAM argument. Yet to run into any issues with VRAM at 1080p. But then I prefer to get as close as possible to 60fps than to max out the AA. But metro 2033 and crysis 2 were doing 1080p and 4x AA just fine - the fps took a hit but it wasn't vram thrashing.

My only advice here is to go second hand, it's not an upgrade worth £180. Ifyou have that to spend your best bet by far is to sell your 5870 for 130-150 on an auction side, add the money to your budget, find another 30 quid from somewhere and buy a gtx580. Second hand 5870s on here, however, go for 120 which is a worthwhile spend in my book.
Click to expand...

Wasn't affected by vram? Post your Metro 2033 benchmark here then.

comp.jpg
 
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