crossfire 16x 4x

[dep3kuj]

Hi guys. Want to ask about crossfiring pcie 3.0 16x and pcie 2.0 16x (@ 4x). I know that it´s not perfect, but is it ok at all? I have asrock fm2a88x extreme 4+ mobo (with x4 860k) and in my current situation I can get one r9 270 and then after a few months get another r9 270. I know that single more powerful gpu (like r9 290) is better, but I can't get it know.

With this mobo crossfiring 2x r9 270 will be ok? (and overclocking them both)?

If I would get like 10% fps drop that I wouldn't get, if I used 16x 16x, I can live with it.

And how much fps increase will I get with my CF? With 1 gpu around 30-50, 2 gpus maybe 50-60?

And what about some "stuttering"? I dont have much info about that...

[dragoon20005]

as a person who have seen systems with similar PCI-E setups for high end GPUs

 

the performance cut can be drastic

 

you may even get worse performance than single GPU or the performance gains is only like 10-20% at most instead of 50-60% gains

[SkilledRebuilds]

I have the same issue, always wanted to do it, figured better read up on it...

 

 

,...While they perform fine,.. because I've tested a single card in both slots,.. the 4x slot did not reduce performance that I saw while gaming.

 

However I've heard but not experienced it,. that Latency between cards may be greatly increased because of it and causes it appearing worse than a single gpu's performance.

@dragoon20005 Is this because the 4x lanes are coming from a chipset, not native from the CPU?

 

Yet also heard reports it works 100% flawless..

 

Not1 real answer stating yes or no,.. but always both sides...

I'm just not sure without a definitive answer.

[Sauron]

since the cards aren't very powerful you probably won't see much of a performance drop, but I still wouldn't do it. Wait until you can afford something better.

[dragoon20005]

I have the same issue, always wanted to do it, figured better read up on it...

 

 

,...While they perform fine,.. because I've tested a single card in both slots,.. the 4x slot did not reduce performance that I saw while gaming.

 

However I've heard but not experienced it,. that Latency between cards may be greatly increased because of it and causes it appearing worse than a single gpu's performance.

@dragoon20005 Is this because the 4x lanes are coming from a chipset, not native from the CPU?

 

Yet also heard reports it works 100% flawless..

 

Not1 real answer stating yes or no,.. but always both sides...

I'm just not sure without a definitive answer.

yes and no

 

i not sure what may be the cause

 

but I say I seen users running a 280/x and 290/X CF complaining of poor performance stutter/lag only to see the x16 x4 setup 

[TR0J4N]

i have 2 r9 270xs in CF on an asrock 970pro3 r2.0 board that has the same 3.0 16x 2.0 16x @4x setup you speak of and i get roughly 1.5-2 times the fps in the games i have checked fps in eg lol and warframe and in crysis 3 i went from averaging about 40ish to staying around 60 on the next preset up. i have yet to run a game and have worse fps

[boboman342]

i have 2 r9 270xs in CF on an asrock 970pro3 r2.0 board that has the same 3.0 16x 2.0 16x @4x setup you speak of and i get roughly 1.5-2 times the fps in the games i have checked fps in eg lol and warframe and in crysis 3 i went from averaging about 40ish to staying around 60 on the next preset up. i have yet to run a game and have worse fps

Same

 

I did the same thing! Well, almost. I used 2 r9 270x's on a gigabyte ga970-ud3p motherboard which also had a 16x and 4x pci-e slots. I got around 60-80% higher fps in games like bf4 with no stuttering!!!!!!!! The only thing that couldn't keep up was my cpu and psu. My fx 6350 was overclocked to 4.8Ghz and always pinned at 100% usage in all the games I played. Maybe my gpu usage could go up even more if my cpu wasn't holding them back? My psu was also dying...It was a cx600m and could barely power the two gpu's (non oc) with my cpu oc...My pc would often shut off without warning because of it.

 

I really wouldn't recommend going crossfire/sli with any "budget" cpu, and definitely not if your psu is not up to par. 

 

Until DX12 fixes the vram science of crossfire/sli gpu's, I would not recommend 2gb cards because with the horsepower of them working together, you will be severally limited to 2gb of vram across them.

[dragoon20005]

i have 2 r9 270xs in CF on an asrock 970pro3 r2.0 board that has the same 3.0 16x 2.0 16x @4x setup you speak of and i get roughly 1.5-2 times the fps in the games i have checked fps in eg lol and warframe and in crysis 3 i went from averaging about 40ish to staying around 60 on the next preset up. i have yet to run a game and have worse fps

erm that mobo is PCI-E 2.0

 

AM3+ do not support PCI-E 3.0 but it still backwards compatible with PCI-E 3.0 GPUs

[TR0J4N]

i dont seem to get the 100% usage cpu thing you get apart from in star citizen... and that i think is just sc being sc. most games sit around 60-80% on my cpu because they generally only run in 4 threaded mode. also if you do choose to crossfire and find a game that runs slower than with one you can tell ccc to just run the single card (no cf) by creating a profile for that game and turning it off. which will put the second card to its low power state (basically off) while you play that game.

[TR0J4N]

erm that mobo is PCI-E 2.0

 

AM3+ do not support PCI-E 3.0 but it still backwards compatible with PCI-E 3.0 GPUs

 

you are right i just checked gpu-z my bad... he should do better then as he has a 3.0 slot to use

[dragoon20005]

you are right i just checked gpu-z my bad... he should do better then as he has a 3.0 slot to use

the first slot is PCI-E 3.0 on the A88X which is shared with the 860K CPU

 

but the second is PCI-E 2.0 X4 which is from the Chipset

 

given that dual 270 performs like a 290/X but with only 2GB VRAM

 

I say sell off the 270 and get a used 290/X like Luke/Slick did

[TR0J4N]

as for stuttering i havent noticed much to be honest but i generally turn vsync on

[dep3kuj]

I see your point guys, I know that getting one r9 290 will be a better option, but I cant get it know, cuz it's too expnsive and I don't have them used on sale in my country in Ok condition, only some DOA gpus... buying on ebay is also bad option, cuz shipping costs a lot.

In this scenario second 270 is the best choise for me.

I saw a reply about bf4 getting 60-80% fps boost with this cf. That's great, cuz this a primary game for this pc.

So as I see getting another 270 isn't the best, but still a worthy investment. Probably...)