1600 x 1200 res: 2 x HD 4850 or 1 x HD 4870

[OS43]

At 1600 x 1200 which is the better choice?

 

[dagger]

At 1600 x 1200 which is the better choice?

A single 4870. It use 1gb ram instead of 4850's 512mb. While less powerful than 2 4850 in term of processing power, the 512mb cards will run into a wall at that resolution.

 

[robertito]

get a 4870 then you can always add a second 4870.

 

[karol4]

not out yet.

 

[bydesign]

The 4870 is only about 10% faster and 50% more costly, 2 4850's are the way to go. I have to disagree with Dagger about the wall at 1900x1200, but that's nothing new. Certainly there is a slight hit but, it's not a wall. More importantly it appears that the 4870's 512's will be the ones priced at $299.

 

[B-Unit]

The 4870 is only about 10% faster and 50% more costly, 2 4850's are the way to go. I have to disagree with Dagger about the wall at 1900x1200, but that's nothing new. Certainly there is a slight hit but, it's not a wall. More importantly it appears that the 4870's 512's will be the ones priced at $299.

Id love to see your benchmark that shows the only 10% increase.

 

[hannibal]

Id love to see your benchmark that shows the only 10% increase.

Hard to say, but there is not so big difference in clock speeds. The faster memory is good when using high resolutions and high AA. So the difference is not so big at lover resolutions, but get bigger when using higher... Depends on how high you want to go. 1600*1200 is reasonable high at this moment... but I think that 2 4850 is much quiker even at those resolutions...

 

[B-Unit]

My point was noone has seen a 4870 yet. Lets reserve judgment and numbers until we do.

 

[nottheking]

Hard to say, but there is not so big difference in clock speeds. The faster memory is good when using high resolutions and high AA.

If that's the case, then 22.4GB/sec would've always remained fine for those of us at 1024x768... But it's not, as games get more and more demanding. So the assertion that drastically higher memory bandwidth won't make a difference is utter BS. Remember, while increased resolutions do increase how much writing the card needs to do, then again, newer games with more shaders require continuously more passes (overdraw) in order to create each frame. So if you consider that as a third dimension, even at 640x480 Crysis has a higher framebuffer-related bandwidth load than any supported resolution for, say, Jedi Knight or Half-Life.

It's worth noting that the RV770 is massive leaps and bounds over RV670, in terms of both texturing and shader power; we go from the 3870 with its 16 TMUs and 320 stream processors at 775MHz, to the 4850 with 40 TMUs and 800 stream processors at 625MHz; that's a 101.6% increase for both, yet the card does NOT perform twice as well as the 3870. Clearly, it is being bottlenecked by the memory bandwidth available in the games being used; a new memory architecture helps, but it hardly can cover the fact that in fact, the 4850 has slightly LESS memory bandwidth than the 3870, dropping down 11.1% to go from 72.0GB/sec to 64.0GB/sec.

 

[terror112]

I agree with B-Unit. Nobody has seen a 4870.. But from my Guestimates... I would agree that It might be 10-30% faster than the 4850. The 4850X2 would be much faster because I doubt the 4870 will be twice as fast as a single 4850.. And who needs 1gb of vram atm unless you go into 1920x1200 with AA or higher. 1600x1200 with 512mb is perfect.

EDIT: Somebody should overclock the 4850 to see If the return %performance increase is improved with the % overclocking of the memory. I bet somebody can find a relationship there.
Plus I doubt that the memory bandwidth will make SUCH a difference.. but I am open to be proved wrong.

 

[hannibal]

Clearly, 4850 is being bottlenecked by the memory bandwidth available in the games being used; a new memory architecture helps, but it hardly can cover the fact that in fact, the 4850 has slightly LESS memory bandwidth than the 3870, dropping down 11.1% to go from 72.0GB/sec to 64.0GB/sec.

I didn't say that it does not matter, but it does not douple (or even make it 50% faster) the performance of 4870 compared to 4850.
So the original ansver is that two 4850 is better for resolution 1600*1200 than single 4870... IMHO ;-)

More bandwidth is allways good, but if the 4870 is $100 more expensive than 4850, the 4850 is better bang for the buck. But as terror112 says it would be interesting to see the difference. Most propably the prize of 4870 will drop more rapidly because gddr5 is so expensive in the beginning, just like ddr3 was (and still is) compared to ddr2.
It's allso true that 4870 may turn out to be fast enough alone, so it may be better to buy one and make it cf when the prize of GDDR5 drops down. In future the games will be even more taxing like nottheking said above!