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Lynnfeild perfoms great with crossfire!

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September 30, 2009 8:01:02 PM

I'm surprised that there are no discussions about this on the forums:

http://www.tomshardware.com/reviews/radeon-hd-5850,2433...

This shows that the x8/x8 bandwidth does not, in fact, hinder multi-GPU performance by anything tangible. This is likely because of how the PCIe bandwidth is used on Lynnfield. Regardless does this mean that Bloomfield is only for the ultra enthusiasts and those wants 3 physical GPUs? Well I think that bloomfield is overpriced to say the least and that Lynnfield is the better buy, but that is me.

Opinions?
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September 30, 2009 8:12:05 PM

I dont think anyone was expecting *this* round of cards to saturate 8x 8x, but there must be a real danger of next series.

We'll know soon enough if somebody does 5870x2 crossfire on it. I would expect those to saturate 8x, possibly losing 20% or so performance.
September 30, 2009 8:39:52 PM

Actually, atleast from what I heard, a lot of people were questioning Lynnfield solely for the 5870 and 5850 crossfire performance. Also if you remember Anandtech's review of 2 4850s in crossfire on a P45 a while back there was a large difference ~ 10 FPS+! With Lynnfield there isn't even a 5 FPS difference and in a single benchmark Lynnfield does better. I think this clearly shows that the PCIe controller implementation in the CPU is a very good idea and may become the future, especially if it makes up for the loss in bandwidth. Imagine if AMD or Intel come out with one that can do that but at full X16/X16!

Maybe I'm just overly impressed by this but it really makes Bloomfield look unnecessary for dual GPU setups.
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September 30, 2009 11:40:07 PM

depending where you live the pricing between 1156 / 1366 socket cpus and mobos can make all the difference.

In the uk there isnt such a hug difference between the two - based on cpu / mobo / ram costs

A lot of people were expecting the lynnfield set up to be more in line with existing C2D boards etc - after all they are supposed to be almost a direct replacement for the C2D.

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October 1, 2009 1:15:33 AM

Yeah I was looking that that chart as well.I've seen many on this board who advise getting a i7 on a X58 board rather than the i7's on the P55 boards if they want to crossfire or sli.The difference wasn't significant except for the price of the motherboards.Also people were surprised how well 4 way crossfire in 4X4X4X4 performed on the mid range AMD SBM.The builders made it perform about as well as an i7 system in gaming.So the difference between 16 X 16 and 8 X 8 really isn't that much just a couple of percent. So those hesitating against going the P55 Lynnfield route have nothing to worry about.

October 1, 2009 1:37:15 AM
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October 1, 2009 1:37:25 AM

Anandtech did find differently however? From their review they did start finding bottlenecks, and generally they push the limits a bit more.
October 1, 2009 1:39:16 AM

I think the main difference was that Tom's overclocked it a bit higher, to a similar level as a common 920 overclock (3.6 GHz+).
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October 1, 2009 1:49:01 AM

I didnt pay the article a lot of attention tbh, but you should be able to find it on anandtech easily enough. There were definite bottlenecks found, I dunno what that means when THG didn't find them though.
October 1, 2009 2:43:35 AM

Here it is:

http://anandtech.com/mb/showdoc.aspx?i=3649&p=1

One thing that is bothering me. Anandtech's conclusions do not match the rest of their articles. They were the only ones who criticized the 5870 even though they had some of the best results with the card and now they see less than a 5% difference, admit to the impossibility of noticing the difference in games, and yet they still say bloomfield only for multi-GPU. I used to love Anandtech and now I'm starting to dislike them, I guess I will just need to draw conclusions from all the review sites and not just my select few.
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October 1, 2009 4:16:54 AM

Well it depends on how one interprets his conclusions.One reader may see one thing in a sentence or paragraph and another reader may conclude differently in reading the article.
I don't think that he is wrong about his conclusions it could have been written differently though.If one wanted to use a multi GPU setup with high end expensive graphics cards or even use 3 way SLI it's obvious that the builder would want to eek out every performance advantage possible.Would it be cost effective probably not and that's why the P55 i7 is a better buy.Look at the TPD of the P55 i7's vs the X58 i7's those X58 i7's need the best cooling possible which really adds up the price.The power consumption on the X58 i7 systems like his graph showed in his article is much higher.Now the advantage of the X58 is that it will be used on Intel's later CPU the ultra expensive Gulftown.Few here will get one or even consider it because of it's high cost and overkill.It's stock cooler rivals aftermarket overclocker air coolers in terms of size and weight.I would hate to imagine how huge or heavy an aftermarket enthusiast CPU air cooling heatsink and fan would weigh or how powerful and loud the fan is.It seems to me that those interested in the Gulftown would probably utilize liquid cooling or phase change cooling for this beast if they want to do some good overclocking.Anandtech's conclusions showed a 2% to as much as 7% difference in CF between the X58/P55 on CF 5870 cards.Probably a better match for the P55 i7's and much more economical would be 2 5850 cards CF'd when they are available very soon.The Radeon 5870 cards are just too costly for their performance next to the 5850 cards.Prices will drop on these as time passes just like the Radeon 4000 series.It depends on how much one wants to spend on a system.To each their own.A P55 i7 system is great for the bang per buck and a very powerful platform.Not the fastest out there but who cares really.

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October 1, 2009 4:28:16 AM

Lynfield has a built in 16x PCI-E controller, where as the P45 it goes via the NB.
So I would think, that 8x on the i5 would have the same speed but lower latency?

Just an idea I was thinking of, don't take it as gospel. I was just thinking that lower latency could be providing bigger advantages than expected?

Could explain P45 on Anandtech vs P55 on Toms.
October 1, 2009 10:40:38 AM

That is what I am saying Spider.

I agree the article's meaning depends on the reader, but that was a pretty black and white and close minded conclusion.
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October 1, 2009 11:38:35 AM

I have to admit i was surprised to see such a small bottleneck from the 8x/8x throughput with the LGA1156 and the 5870s in crossfire. I was expecting to see a much bigger hit and it's less then 5%. I wish they'd done the same tests using a PhenomII x4 and a 790GX/790FX to see how the 5870s do in an AMD set up.
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October 1, 2009 12:29:22 PM

Like I said, I believe this generation of cards will be fine, except the x2's. It's next years cards I'd be worried about, they will surely bring the end for 8x 8x.
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October 1, 2009 1:00:25 PM

dirtmountain said:
I have to admit i was surprised to see such a small bottleneck from the 8x/8x throughput with the LGA1156 and the 5870s in crossfire. I was expecting to see a much bigger hit and it's less then 5%. I wish they'd done the same tests using a PhenomII x4 and a 790GX/790FX to see how the 5870s do in an AMD set up.


Well Toms Hardware I don't think had a direct comparison but they had several articles comparing a 790GX system against their last i7 SBM system here using the 4000 series.
http://www.tomshardware.com/reviews/cyberpower-gamer-dr...

It didn't fare too well.Then they next used a 790FX motherboard and tried again against the i7 SBM system here it looked better but still came up short again
http://www.tomshardware.com/reviews/phenom-versus-i7,23...

Finally on their current SBM they built a 790FX system that could match the earlier i7 SBM system in gaming using 4 way crossfire in 4X4X4X4 mode.
I was surprised at the outcome.Heck I have a 790FX system and I think I should upgrade using the cards in their build.I didn't think that 4 way crossfire would do well either in 4X4X4X4 but clearly the benchmarks show otherwise.

http://www.tomshardware.com/reviews/amd-enthusiast-cros...
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October 1, 2009 1:14:23 PM

4x 4850's. They are probably losing a very small amount per card but nothing to hurt the obvious performance that 4 of those would bring.

That would stack up with 5870's losing a very small amount at 8x. There is no major hurt going on here but it is something that is on limited time, hence the coming changeover to pci-e 3.0.
October 1, 2009 2:30:47 PM

I'm really interested in seeing how an AMD Phenom II platform handles multiple 5870/5850s. Remember Tom's articles comparing it to i7 (not SBM) came out before the recent driver updates that supposedly increase crossfire performance on AMD platforms.

As for gulftown, I'll wait awhile before I upgrade my quad, as should anyone else. We also have to expect it to come in at $1000+ until AMD comes out with it's 6-core.
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October 1, 2009 4:45:46 PM

When the Intel quads were tested on the P45 8x/8x platform with the 4870s some sites showed loss of performance when compared to the X48 platform at 16x/16x. I thought this would carry over or even be worse with the P55 8x/8x and the 5870s.
http://www.tweaktown.com/articles/1472/intel_p45_vs_x48...

So far all the benchmarks have shown that it isn't the case. I do wonder if they retest the Q9550 LGA775 and the P45/X48 along with the PhenomII x4 955 and the 790GX and 790FX if they'll be bandwidth limited and if the great 8x/8x performance of the LGA1156 and the i5 and i7 is due to the CPU and the platform.
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