HD4870 Crossfire Issues

I have two HD4870's in my PC. And I have CrossfireX enabled through CCC, now I asumed I had crossfire up and running properly, but Gpu-z and other benchmark software seem to think differently.
Now I obviously do have Crossfire enabled as there is a 2,500 difference in 3dmark, but I just have a feeling CF is not functioning properly on my setup.(I added pics to show you just some of the benchmark/utilities that say crossfire is not enabled.

I have done 3Dmark tests with CFx on/off and there seems to be some difference. I get 14,000 with one 4870, and 16,500 with two in Crossfire. And to be honest that difference doesn't seem as big as it should be(let alone the fact I should get more then 14k on a single 4870)

Also does it matter if I use two or a single crossfire connection between cards, I don't think it matters does it?


(I'm using a ASUS P5Q premium board, so the second PCI-E 2.0 is x8 link but I still should have big increase regardless)

P5Q mobo, 4GB 800Mhz RAM, 2x Sapphire ATI HD4870, E8500 3.16Ghz, antec1000w PSU, windows XP.





Thanks....

Well it looks like your board runs 8x + 8x first of all.

Also your score in 3Dmark06 looks fine to me. If you want those big numbers you think you should get, overclock that cpu to 4.0 and you should be 20k no problem. You cant expect much at 3.1.

I think you just found out what many others have found out before. Xfire/SLI is way over rated for the extra price you pay.

Yeah the mobo is PCI-E 2.0 x8 link when in Crossfire was aware of that when buying(got good deal) but should be good improvement over single card.

And the crossfire connectors don't seem to matter what order they are in. I used 1 connector then both connectors, swapped them around ect ect. All the same.

Would I be right in presuming that because its not 16x2 and 8x2 that maybe the software utilities/benchmarks are just not reading it right, or perhaps because the HD4870 are new?

All I know is that when I had vista(downgraded last week, formated HDD and new XP sp3 install, no errors doing it and everything is fine so I don't think that has to do with it) gpu-z had Crossfire(enabled).

So perhaps its a CrossfireX on xp issue?

Thanks...

Nah I don't have anything running in backround that would throw CCC off.

I'm starting to get vexed with the feeling my 4870s are underperforming.

I wonder would my RAM be bottlenecking, cause everything else is good. 1000W antec PSU, good E8500 CPU.

I have 4GB 800Mhz RAM, 2x1GB are CL4(well suppose to be they are meant to be 4-4-4-12 but my mobo sees them as CL5 regardless of whether other higher cas ram is installed or not) and the other 2x1GB are CL5, and on top of that Im using 32bit XP so it only sees about 3gb, the two 4870s are using up 1gb themselves.

There ok, Crysis does suffer on DX9 High on 1440*900 if I stick AA on.

But it is very smooth with AA off. And if I recall the higher the res may actually perform better or no worse. Something to do with GPU doing more work and less pressure on CPU or some lark.


I have my E8500 clocked to 3.6Ghz now and the two 4870s at 790/1100 over the stock 760/900 and get just under 18,000 on 3Dmark 06.

I don't think there is a MB available that will render true 16x2.0 in SLI or Crossfire.

Appreciate it, Its just with all the overbloated 3Dmark scores and crysis benchmarks here I was feeling like was underperforming. But theres always going be people gettitng silly scores, should stop trying to match them

I have a Zalman CPU cooler on its way so once Im in the mood to take mobo out and install it again Ill stick it on lol, try get 4ghz.

http://www.tweaktown.com/reviews/1 [...] index.html

This is kind of old but right on the mark with your scores..13-.14K for one and 16K for two. Given they had a quad vs there have been a few driver improvements and you have a dual core...I think that is about right.

I bet you could get over 17K and beyond but you will have to push your CPU harder, bump your RAM frequency up from 800, get your GPUs to 790/1100... 3Dmark is all about the CPU though...I bet your system chewing up games ans spitting them out.