4870 crossfire scaling w/ core i7?

[EskLuxor]

anyone try this combo? prolly not alot of people. i just built a new system for the first time in 2 yrs. i have a 4870 from my last system and was playing with the notion of picking up a 2nd for the time being and crossfire it. (instead of spending $300+ on a new vid card)

new system:

core i7 2600k @ 4.0ghz
asrock z68 extreme 4 gen 3
cooler master 212+
cooler master haf 942
corsair hx850 psu
corsair force gt 90gb
wd black 1tb
16gb averix 1600mhz
asus xonar dx
lg 12x blu burner
lg 22x dvdrw
card reader

no vid card yet. :/

 

[GotNoRice]

What is your question exactly?

It should work fine, giving you approx the performance of a single 5870.

I'm currently running 2x 4870x2 in Quad-CF on my i5-2500K @ 5Ghz and everything works perfect. There are no issues due to the cards being old, and despite the cards only being DirectX10.1 hardware, DirectX11 games will still run just fine using the DirectX10.1 feature level.

As far as scaling goes, it should scale just fine, though perhaps not quite as well as the 6-series. My 4 4870 GPUs are good for over 32K (GPU Score) in vantage whereas a single 7970 would score ~28K.

 

[lavaheadache]

What is your question exactly?

It should work fine, giving you approx the performance of a single 5870.

I'm currently running 2x 4870x2 in Quad-CF on my i5-2500K @ 5Ghz and everything works perfect. There are no issues due to the cards being old, and despite the cards only being DirectX10.1 hardware, DirectX11 games will still run just fine using the DirectX10.1 feature level.

As far as scaling goes, it should scale just fine, though perhaps not quite as well as the 6-series. My 4 4870 GPUs are good for over 32K (GPU Score) in vantage whereas a single 7970 would score ~28K.

all is well till you play a game that doesn't scale all that well.

Play Skyrim and tell me how many GPU's it uses. I tried on my older 4870 trifire setup and only 2 gpu's worked which weren't enough @ 2560x1600

 

[EskLuxor]

basically just wondering how well they would hold up in games. despite their age and gpu architecture. which u answered thanks.

 

[kalrith]

You should compare the cost of a second 4870 with getting something like the 5870 and selling your 4870. The difference might not be that huge, and it would resolve the potential problems of scaling and microstuttering.

 

[EskLuxor]

i checked into that, im just comparing costs. a 2nd 4870 might only run $40-60 used. i thought about getting two 6870 as they get about 20-30 fps better then a single 6950, but cost about $80 more. and i dont know if ill have the money later to buy a 2nd 6950 since im buying a house soon.

 

[EskLuxor]

u think TWO 4870x2 would run ok on a corsair hx850?

 

[GotNoRice]

u think TWO 4870x2 would run ok on a corsair hx850?

It's possible, but power consumption of 2x 4870x2 is no joke. They consume more power than 2x GTX580 or 2x GTX480 even, with more heat output as well. With my old Q9650 @ 4.4Ghz I pulled 1173w with furmark+burntest, getting very close to the limits of my Antec TPQ 1000w. Sandy bridge processors are much more efficient and it doesn't look like you're running tons of hard drives so 850 should be ok. Aside from heat/power concerns it is a very solid setup.

As far as skyrim goes, there are some crossfire issues past 2 GPUs but then again this is the same game that ties it's physics engine to your FPS... It's hard for me blame AMD for minor crossfire quirks in a game seemingly written by monkeys, especially when every other game I play runs so well. My 2x 4870x2 ran most games better than my friend's 2x 560Ti to the extent that he got rid of them went back to using a single 6970 lol. I guess getting new cards only to have them shown up by cards from 2008 was just too much.

 

[kalrith]

u think TWO 4870x2 would run ok on a corsair hx850?

I don't know if I would risk it. In this AT review, they hit 752W at load. The article states:

Keep in mind that this power measurement is taken running a 3dmark pixel shader test using almost no other resources. In actual game play power draw is much higher as the CPU, memory, and hard drive can come under load at the same time.

If you want GTX 280 SLI or 4870 X2 CrossFire you'll want to head on up to the 1200W deparment.

 

[EskLuxor]

thanks for all the answers appreciate it.
which single or dual cards would have similar performance/cost of two 4870x2? also, ive never run a crossfire or sli setup b4, do both cards have to be identical; meaning same manu facturer same model #?

 

[GotNoRice]

I don't know if I would risk it. In this AT review, they hit 752W at load. The article states:

But assuming at least 80-85% efficiency, 752w from the wall is only approx 600-650w output. Even when I measured my 1000w PSU pulling 1173 from the wall, that would still be under 1000w output even with 85% efficiency.

A typical Socket 775/1366 processor like the article probably used is also going to use a lot more power than a 1155 Sandy Bridge, like the OP has.

which single or dual cards would have similar performance/cost of two 4870x2? also, ive never run a crossfire or sli setup b4, do both cards have to be identical; meaning same manu facturer same model #?

In terms of performance they would be very similar to a 2x GTX560Ti setup or a 2x 6870 setup. They don't have to be the same manufacturer, you can even mix a 4870x2 with a regular 4870 for Triple-Crossfire.

 

[EskLuxor]

the corsair hx850 is 80 plus silver. the review i read from hardwaresecrets.com suggested that it was more efficient then the cooler master silent 80 plus gold 900w that i was originally looking it.

 

[nurturedhate]

running am i5-2400 at 3.7 with a 4870 crossfire setup originally, both overclocked to 810/1050. BF3 went from 25-35fps (1 4870) to 40-50fps (crossfire) at 1680*1050. So it went from not playable to barely playable. I like tinkering with my system, I enjoy the poking and prodding but having to constantly adjust and fiddle just to get playable is a far cry from messing with stuff to get 5fps more and already playable levels. Kinda sucks the enjoyment out of it.

4870s are also ovens. Literal space heaters. They suck power and are LOUD. In the end it was far better upgrading to the 580.

In the end I would have to say:
BF3 - not playable
Witcher 2 - completely playable, seemed to scale well in crossfire
Skyrim - at the time was more cpu bound, playable gfx's wise at base, not with HD texture mods
Dues Ex - Playable
World of Tanks - Playable, didnt have an issue with the ati scope issue
WoW - well, yea, def playable
Starcraft 2 - didn't seem to scale well, playable on a single 4870
Rage - played surprisingly well, didn't think it would originally, took a driver update

Overall, you'll need to stay ahead on your drivers and caps from AMD. In the long haul I suppose it's going to be more about what you built the system for. If all you do is play some older or less demanding games then they will work fine. If you are actually trying to game and thats the systems main purpose save some money and buy a decent card.

 

[nurturedhate]

two other things to add - psu was a corsair tx650 and i swear that i had an easier time seeing through foliage, shadows and such in BF3 with the 4870s even using the same graphics setting, albeit nvidia v amd. maybe something to do with the way dx10.1 functions.