Single 4870x2 or dual 4870x2 ?

emesh147

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Hello, I've searched the forum but haven't found a similar thread. If one exists please refer me to it.

I've been thinking about buying a AMD/ATI 4870x2 (I heard Saphire should be a good choice...). And then I found myself thinking about Crossfiring two of these.

So my questions are as follows:
1. I understand there is a partial similarity between using a 4870x2 and using two cards (say two 4870). How much performance would I gain, Crossfiring two 4870x2?
2. How noisy is such a configuration bound to be?

Thanks in advance!
 
im not sure what your asking but 4870x2 would be better than two 4870
in benchmarks 4870x2 scales little bit better...also you will only need one 6pin and one 8pin connectors as opposing to four 6pin connectors for two 4870's (each card needs two 6pins) and single card would be better since it will be single heat source opposing to two heaters haha
 

B-Unit

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Unless your on a large (30" or bigger, huge resolutions) monitor, the second x2 wont help at all. One of these cards is plenty even for most enthusiast class machines. Also, unless your on an i7 rig, you probably will be limited by your CPU.
 

einstein4pres

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There are diminishing returns for using quad video cards over two video cards.

What resolution are you planning on playing at? What sort of games do you play?

One 4870x2 plays most games with great FPS.
 

emesh147

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Well first, my computer monitor is a 32" TV and let's say I'm not sitting too far from it :) Having said that, its native resolution is 1366x768 progressive, which sucks, or 1920x1080 interlaced, which is actually pretty nice for video, and for games it does a sort of AAx2 effect. I may buy a new 1080p TV (unlikely) or 22" monitor (likely) in the future, but regarding this purchase let's assume I'm stuck with this one forever.

So, you guys have pointed out two issues: CPU bottle neck, and performance gain only in really high resolutions, probably higher than 1080i. So since high resolutions won't be reached, I'm left with the CPU bottleneck, and therefore I think I should present my current configuration (which is about 16 months old):
- Motherboard: ASUS P5E-VM HDMI (Intel G35, PCIe x16)
- RAM: 4GB
- CPU: Intel Core 2 Duo E6750
- Graphics: ASUS nVidia 8800GT 512MB
- HDD: 2x300GB WD on RAID-0
- Sound: Creative X-Fi Xtreme Audio PCIe
- OS: Vista32

A note about my configuration: I am open for suggestions on improving it, including changing motherboard/CPU/OS etc', but only if I have to.

As for what kinds of games I play, here's a list of my recent games:
- BioShock
- Crisys
- Racedriver GRID
- Far Cry 2
- NFS Undercover
- GTA IV (the best game ever)
- Mirror's Edge
 

emesh147

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Do you think I'd be limited by my CPU (E6750) when using only one 4870x2?
I imagine I'd be limited by my motherboard cause it doesn't have PCIe 2.0... But I'm not sure how big the difference in performance should be.

I just want GTA4, Far Cry 2 and Mirror's Edge to render more FPS (much much more), how would I know if the difference in performance is worth the money of a new CPU and motherboard?
 

antiacid

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Here's the bottom line:

a single 4870x2 can max out even a i7 965 in certain conditions. Going crossfire makes this even more prevalent. Note that XF does not yield a 2x increase in performance. It's more like 1.1-1.8 times depending on the settings, game, cpu, etc.

You game on a low definition monitor (from a pixel count perspective). A high definition monitor like a 24inch (1920x1200) or a 30inch display (2560x1600) is really the better playground for a 4870x2. Even at 1080p (which is 1920x1080 on a 21-22inch WS monitor for example), your 4870x2 will not be sweating too hard.

You run a cpu which is only a dual core and running 2.66ghz. That's like putting Lance armstrong on a tricycle. Sure, you'll have the fastest tricycle around the neighborhood but you'll still be far from your potential.

So I guess what I'm trying to say here is that it is a good buy but in your case, you might be better suited to get a 4870 or a gtx260+ and spend the extra money on a nice 22-24 inch display. In the line of upgrades, you can bump that E6750 for a q9550 or something similar which can be pushed to 3.5-3.8ghz with proper cooling.
 

L1qu1d

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I've seen soo many benchmarks showing the 4870 X2 is slightly slower than the 4870 in Crossfire. Although they do exchange blows sometimes:)

Google it cuz I'm too lazy to look for it agian:p If you don't google it just ignore this. I'm too lazy to back up my reasoning this time haha

but all in all I think the lose in a couple of frames is worth the extra slot:)
 



The size of TVs does not matter, what matters is the resolution. Your current 32" HDTV is 1366 x 768; you will not gain any performance increase with a 4870x2 XFire setup. Currently all HDTVs max out at 1920 x 1080. At that resolution you will probably get a little boost compared to a single 4870x2, but for most games an XFire setup for that resolution is not really worth it unless the game is poorly coded. GTA IV is an example as well as Crysis.

What B-Unit was referring to was a 30" LCD computer monitor which has a resolution of 2560 x 1600. This 3.9x the amount of pixels compared to your puny 1366 x 768 HDTV. That is almost 2x as many pixels as a modern 1080p HDTV.

That's what XFire and SLI are truly for.
 

emesh147

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That's a nice analogy :)

So, suppose I buy the 4870 and Q9550, do you think adding a board that supports PCIe 2.0 would make much of a difference then?