Hi guys. Wanting some solid advice on how much speed loss you get running a medium priced P55 with x1 16 speed lane and another x4 speed. Obviously if you xfired these they would both be ruinning at x4 speed. The real issue here is 'how much of an impact is it going to have'? Im using a Gigabyte P55 UD3R m/b with a 5850 in me 16 speed. IF i xfired with another 5850 am i going to lose speed? Would it be a better soloution to just splash out on a new board ( which i dont really want to do ) . I see this article http://www.hardocp.com/article/2010/08/25/gtx_480_sli_pcie_bandwidth_perf_x16x16_vs_x4x4/ who doesnt seem to think its much of an issue. Cant say i trust their judgment but if anyone has had some first hand experience of this i would love to hear some feedback good or bad. Im running x3 24" for Eyefinity for me racing sims and could prob use a bit of extra oomph. Starting to feel i should of just paid the extra in the first place and went with an i7. Following specs - Gigabyte P55-UD3R I5 750 @ 4ghz 4BG Coarsir Dominator 1600mhz Coarsiar H50 cooling Coarsir HX850 PSU Creative Fatality X-fi pro XFX 5850 XXX 800/1200 Trusty ol P183 to wrap it all up in.
If you wanted to crossfire the GPU then I'd lok at a better board. x4 pci-e would cripple the card for games & wouldn't make it a worthwhile upgrade for the money.
From what i have found , some seem to think it will cripple the system, others say its a 1-4% hit, others 10%. What i would like to see is some real hard facts about this. I can only assume that a lot of people these days went for one of the more reasonably priced motherboards when the P55 range was introduced. Most are the same situation that 1@16 and 1@4 and i be damnd if i can find anyone whos put it to some hard benches etc. Tis a mixed bag from all angles
Hard facts?.. check this benchmark test with a 5870 on PCI-E 1x, 4x, 8x and 16x. Single cards only unfortunately not crossfire, but you should be able to guage the difference in performance hit on a secondry gfx card. In most of the test conducted, 4x seems to be no more, or not much more than 20fps difference compared to 16x. In some games its about 5fps different.
Well according to that there is no more than a 5% loss. At some game x4 speed was the fastest .... Certainly not as high a loss as i expected it to be tbh. Still not sure how it will affect xfire performance though. Impressive results indeed, as they said only the most hardcore enthusiast would notice that. Maybe the budget P55 is more attractive than first thought.
You probably lose a few fps, nothing big. Doesn't say much for how much we are using a 8 or 16 lane though
ive been up and down on running crossfire on the UD3 and i still dont know what ill do long term. i was so disappointed when i learned (after purchase) that the slots were clocked down to x4/x4 when running crossfire, but now my hopes are slightly raised...again. on a side note...since you have essentially the same hardware as me spanky, how do you like that 5850 overall? i mean other than not being able to power 3 24" screens...i would only be running my 22" and 19" and not in eyefinity...
That 5850 is a little powerhouse mate. I DO run my Eyefinity sweet on it 5760x1080, only in BFBC2 do i have to run it only on the Medium settings, and to be fair i some of them up high it still runs pretty sweetly. I just wanted to know ( out of pure greed ofc ) if slapping another one in is gonna do me some justice. I have been mulling over motherboards all night and i see a GD65 for £109 on Ebuyer. Shall i , shan't i? I dont know mate. Gut say recycle the UD3R on ebay, should get near £80 for it i reckon from the non savy ebayer and do it that way. But if you are thinking of getting a 5850 then dont be put off by my comments about struggling under eyefinity because it kinda not that true. I do play racing sims mostly though, Rfactor GTR2 even with 20-30 cars on the grid it runs very very sweet. I would still like to hear from anyone thou who does run with a 16x4 CF and see what they have to say about it.
the performance dif is around 10% vs 16 x 8 ( tomshardware has a review that shows the diffrences with 480s in sli on a 16 x 16 16 x 8 16 x 4 8 x 8 8 x 4 4 x 4) 16x 16 16x8 8x8 showed no perforance dif at all. 16x4 was 5% down on the other 4 and 8x4 was 10% down. 4x4 was 20% down and this is in sythentic benchmarks. and still 10% at 16x16 ( cards are not bandwidth capped on 8 slots let alone 16 ) its still a performance upgrade
I can vouch for the 5850 aswell. Had mine running in eyefinity 5040x1050 and I didn't have to lower a setting, ok maybe i had to knock some AA off in BC2, but the framerates stayed above 35
Check out these articles over at hardocp.com: http://www.hardocp.com/article/2010/08/25/gtx_480_sli_pcie_bandwidth_perf_x16x16_vs_x4x4/ and: http://hardocp.com/article/2010/08/23/gtx_480_sli_pcie_bandwidth_perf_x16x16_vs_x8x8/ Fascintaing stuff!
