I got a 8800GTS 640 now, but when I buy a new MB some day I wonder if I should buy a MB that supports CrossFire or one that supports SLI. If buy a MB with CrossFire-support, I think I'm gonna buy a couple of HD 3870s, but then I have no use for the 8800GTS I already have. But would two HD 3870s beat two 8800GTS'?
 
Thanks

Radeon 3870>8800GTS 640 generally speaking.
 
http://www23.tomshardware.com/grap [...] &chart=315

Dont look at 3D mark. Look at over all Frames, The 640 has the extra ram that should give it the advantage at high Resolutions
 
http://www23.tomshardware.com/grap [...] &chart=318
 
Prey
http://www23.tomshardware.com/grap [...] &chart=301
 
Warhammer
http://www23.tomshardware.com/grap [...] &chart=305
 
battlefield  
http://www23.tomshardware.com/grap [...] &chart=277
 
Dark Messiah  
http://www23.tomshardware.com/grap [...] &chart=282
 
It only looses at 3Dmark and Doom3. And not by alot!
 

Ok, thanks. Sry for double-post btw..
I'm using a 22" monitor on 1680x1050 now, so I don't know if there will be a hole lot difference between 640 and 512MB.. Maybe with lots of AA/AF..?
And who got the best drivers for multi GPU setups..?

 
Sorry but over all, the GTS still comes out on top.
 

 
As far as SLI/Crossfire goes....
I would prefer the Crossfire setup.
I believe that the GTS SLI and 3870 CF will perform similarly but I have a dislike for nVidia's motherboards.
 
Before you replace anything, why don't you try to overclock your GTS?
I am running a GTS 640 on a 22" also and can personally attest to the performance gains to be had.
If you still want to spend some cash, wait till the 4xxx series comes out before you make a jump.
Only another month or two left so might as well.

If you wait another month or two, the new ATI cards should be out, which would be better than either two cards you mention.

You can't assume look what happened witht he 9800 GTX

Just like the 2900XTX 'GTX Killer', oooh I can't wait.

After the 2900 fiasco and the 9800 fiasco ATI would do its homework for sure

 
Do you mean the XTX 2900 that was never produced because it ran so poorly? I'm looking forward to the ATI 4xxx series cards myself, but I'm making no judgments until the actual benches are out.
 
@OP- I have owned the 8800 GTS 640 and now have a 3870. They perform almost identically, but the 3870 seems a bit more stable (better drivers?) and the 3870 is a lot quieter, which I like. Since you have a 8800 GTS 640, I'd wait until the new ATI 4xxx series cards come out before buying something new. Even if the 4xxx series don't perform as well as expected, the 3870s should come down a bit in price, thus making the purchase even better. Your monitor is the same size as mine and Crossfire would help in some games and not in others. A larger monitor and I think Crossfire would be the way to go, but at 1680x1050, the monitor size seems right on the edge of whether or not its worth it.

Thanks for replies (:
I would have waited a couple of monts anyway, and now I got even more reason to do that. Someone know if there are major changes on the 4xxx?
Btw outlw I run the card on 650/950 (:

I had the 640mb 8800GTS in SLI @620/900, and, before one card failed, the performance was stellar, I was really impressed compared to my experience with two 7600 GT's in SLI. Now I have a single 9800 GTX @800/2000/1185) which beats the old 8800GTS SLI setup in some games (Crysis), but not in others (ET:QW, COD4). I haven't played with the 3870 in CF but my personal experience was ace with two 8800GTS models in SLI (this would be a hi res testimonial at 1920x1200, so I don't know how it would play out at your res) was good.

I have a HD3870 in my second PC and it's WAY slower than my 8800GTX at stock.

I also have a 8800 GTS 640 in Sli @612/1404/900 and it's worth it, specially now when you can get old GTS for cheap. BTW I'm playing at 1680x1050 same as you and the difference between one card and SLI is huge so I would say go for it.

I have an 8800GTS 640 PCIE 16x, but I prefer my Radeon 3870 PCIE 2.0 at 16 x 10.  If I were to SLI/Crossfire, I would choose the X38/48 chipset in Crossfire over any nvidia SLI chipset available.  Just my preference.

 
 
Installed in my system my Radeon 3870 performs better than my 8800GTS 640.  

I adore my 3870 crossfire setup on a X38 mobo. I'm running them on a 24" Sam'y and get minimum 60Fps with all my games (inc COD 4) maxed bar of course Crysis. Plus i think Crossfire has a better driver support and works with most if not all games generally better than SLI.

Single card head to head nVidia. But i would say Crossfire over SLI unless using gt/gts/gtx.

Its a well known fact that sli is alot better than crossfire, escpecially since the crossfire had alot of compatibility issues.
 
I'm not saying that to bring any1 down, but its realistic, if I find the article again for you guys I'll post it. you guys are free to look into it.
 
As for the 3870 vs the 8800 GTS 640, I'm a little skeptical because now that I look at it, the 9600 GT is a better card than the 8800 GTS (G80) and it still doesn't outperform the 3870 (with out AA on).  
 
I'd say from estimates that, the 3870 would be around equal to with filtering on, while with out filtering it would surpass it.
 
Either way the 3870 is a better investment. I noticed that the charts on THG are out of date with the drivers.

I have 3 SLI systems in SLI running.  I use two of them every day.  I'll take my X38 with the 3870 over the three put together.  It towers over them.
 
Oh yeah, I paid $310 for my 8800GTS 640 about 6 months ago.  I bought my Radeon 3870 for $139 after rebate a couple of months ago.  Call it even if you want.