XFire on a P35 Board?

[dadi_oh]

I have an ASUS P5K-E Wifi board with 1 PCIe-16X slot and 1 PCIe-4X slot. I was thinking of going to a 4870 in the PCIe-16X slot and further down the road adding another 4870 in the 4X slot when prices drop.

Would the 4X slot be a HUGE bottleneck that would basically wipe out the benefits of XFire or is it a minor reduction in performance?

Thanks

 

[FR@NK]

It will be slower and i wouldnt recommend it...but you might not notice the slow down in games.

 

[ShadowFold]

A P45 and a HD 4850 would perform better than 16x + 4x 1.1 crossfire honestly

 

[erocker]

Or, get a 4870x2 or 4850x2.

 

[dadi_oh]

A P45 and a HD 4850 would perform better than 16x + 4x 1.1 crossfire honestly

You mean a P45 with Xfired 4850's is faster than a P35 with Xfired 4870's?

I am just looking down the road to potential Xfire. I have a fully watercooled setup so swapping out my mobo is a "bit" of a pain (but not out of the queston).

 

[dadi_oh]

Or, get a 4870x2 or 4850x2.

The 4870X2 are a little out of my price range at the moment. Never heard of a 4850X2... Will need to do some research.

Thanks

 

[JrRacinFan]

Hmmmm ....

8800GT -> HD4870 as an upgrade? Do you consistently game at 1680x1050?

 

[dadi_oh]

It will be slower and i wouldnt recommend it...but you might not notice the slow down in games.

That's what I am trying to determine. If it isomething like a 10% penalty in games then no big whoop. If it was like a 40% slowdown then probably not worth it.

May need to do some more searching to see if someone has some benches with a P35 in Xfire.

 

[JrRacinFan]

IMO, wouldn't be worth it unless you know you will be getting a new motherboard soon after getting the second HD4870.

 

[dadi_oh]

Hmmmm ....

8800GT -> HD4870 as an upgrade? Do you consistently game at 1680x1050?

Yes. My monitor is a Samsung 226CW at 1680X1050. To be honest all of the games I play right now are fine with my 8800GT. (COD4, UT3, BF2, BF2142). Just looking to the future a bit. Doesn't take much of an excuse for me to get new HW

I do a lot of folding and I thought I heard that the 48xx are not up to the Nvidia performance (yet). Could be wrong though... My 8800GT gets up in the 4500-5200 PPD range depending on when you look at FAHmon.

 

[JrRacinFan]

Yes. My monitor is a Samsung 226CW at 1680X1050. To be honest all of the games I play right now are fine with my 8800GT. (COD4, UT3, BF2, BF2142). Just looking to the future a bit. Doesn't take much of an excuse for me to get new HW

I do a lot of folding and I thought I heard that the 48xx are not up to the Nvidia performance (yet). Could be wrong though... My 8800GT gets up in the 4500-5200 PPD range depending on when you look at FAHmon.

Can't really disagree with that! But see my previous post regarding crossfire on the P35.

 

[phantom8]

I've read some review on crossfire performance on a P35 vs P45. The difference is insignificant.

 

[dadi_oh]

I've read some review on crossfire performance on a P35 vs P45. The difference is insignificant.

OK. I will search for some reviews. You don't have a link handy do you?

 

[Tatty_Two]

I read loads of reviews on this subject when the x38 chipsets came out (because I was toying between the 2 chipsets....I went for x38), comparing crossfire performance between P35 and x38, they used HD3870's and the performance hit across the board was 10-15%.......however, with a 16 x 4 setup on PCI-E 1.1 boards, the hit gets greater the better your cards are, quite simply because the slot is holding it's power back more if you get my drift, so at a guess (and thats all it is) I would suggest perhaps 15-20% hit with two 4850's and perhaps 25% with 4870's, now that may be a bit ambitious and I would think that would be the max bottlenecking but it can at times be significant, and for that reason alone personally I wouldnt go for it.

IMO I would keep your very respectable P5K-E and either go 3870x2 or 4870x2 (if you can afford it) in a single slot..........but TBH, a single 4870 will do the job.

 

[mrhuggles]

its not much slower, infact its not really any slower at all, try it it rocks, i have a asus P5k normal its great for that.

not like 10% more like less than 1%

except in load times ofcource.

and if you can consider p35's overclocking capibilities then it will be a better performer than the p45 for sure... altho ive heard the x38 is better the x38 sure is expensive :?

 

[Tatty_Two]

its not much slower, infact its not really any slower at all, try it it rocks, i have a asus P5k normal its great for that.

not like 10% more like less than 1%

except in load times ofcource.

and if you can consider p35's overclocking capibilities then it will be a better performer than the p45 for sure... altho ive heard the x38 is better the x38 sure is expensive :?

X48 16 x16 versus P35 16 x 4 (in FPS at OP res of 16xx with crossfired HD4850's)........

"Devil May Cry 4"

X48 - 207FPS
P35 - 154FPS.....around 25% hit

"Supreme Commander"

X48 - 77FPS
P35 - 55FPS..............around 28% hit

"World in Conflict"

X48 - 48FPS
P35 - 33FPS..............around 32% hit

"UT3"
X48 - 123FPS
P35 - 111FPS........around 10% hit

Now that only tells part of the story because it compares the top end x48 @ 16 x 16 and of course there are also the chipset improvements to account for, there are some games where there is only about a 1 or 2% performance difference, but largely thats not because of the small differences in those games between 16 x 16 and 16 x 4 but due to game crossfire scalability/efficiency.....Crysis is a good example of that.

If you bought an X45 or 38 board instead, you would only narrow the hit P35 takes by around 1%. To be fair however, there are games out there where the difference is much narrower.

http://www.legionhardware.com/document.php?id=761&p=8

 

[mrhuggles]

i wonder what those results would be like against a well overclocked asus p5k board

 

[Tatty_Two]

i wonder what those results would be like against a well overclocked asus p5k board

Probably similar because then....to make it fair you would have to overclock the X48 or 45 board, and of course Asus makes some mighty overclockable 45 and 48 boards as well.

 

[dipsta]

dont do it i had the same set up on the same mb as you, with 4850's it was rubbish to say the least, massive problems in crysis had to disable xfire to get it torwork right.
now upgraded to 4870x2 much better.