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HD 4870... What AMD CPU will be bottleneck free?

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December 26, 2008 8:54:41 PM

I know AM3 is coming out soon, but I've decide to wait to build an AM3 system until summer when everything is mature and prices are lower (unless am3 is going to be better price to performance ratio than rock bottom priced phenoms and athlons? if so enlighten me please). If not, I am wondering -

A. What CPU one would pair with an HD 4870 so there arent bottlenecks. I was thinking the new Kuma dual core relabled black edition phenom.. It is a great little CPU (77.00) when talking price to performance, however it is pointless if it would limit the 4870. There is also a 9600 for 99.99$ today, and triple cores are down alot 82.99-92.99, and the black edition trip core is 118$ or something. (but then aftermarket cooler). 9850s are 147.00$. Whats the best match price/performance wise.

B. Is it worth spending the extra 15-20.00 for DDR2 1066 for the marginal performance gain?

Thanks!
a c 172 à CPUs
December 26, 2008 9:09:47 PM

A. I don't know about AMD processors, but I suspect that a modern video card will start bottlenecking at a CPU speed of 3.2 - 3.3 GHz.

B. I don't think so.
a b à CPUs
December 26, 2008 9:16:58 PM

I thought about making a joke about some Intel processor being called an AMD... but I won't.

Not sure what to tell ya man.
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a b à CPUs
December 26, 2008 10:26:46 PM

Personally, I would get the Phenom 9850. However, you may be just fine with only 2 or 3 cores, depending on what you do most of the time. Quads are fabulous in processing videos or Flight Simulator X or various kinds of work. Higher-clocked dual cores can beat them in games, on the other hand.
Anyway, if you can afford a quad get one. It's more future-proof.

This article might help you a bit:
http://www.legionhardware.com/document.php?id=775&p=2

a b à CPUs
December 27, 2008 12:20:49 AM

Imo, depending on the resolution a 2.8Ghz X2 will NOT bottle neck the GPU.
December 27, 2008 12:53:58 AM

1440x900 will be the resolution for now, so nothin crazy. In 3d bench marks quads seem to score higher than duals with the same GPU, is this soley related on the fact that the benchmark is written for four cores? Or is this the bottleneck? and as far as the ram what do you guys think. Thanks.
a b à CPUs
December 27, 2008 8:50:12 PM

Don't rely too much on 3D Benchmarks. Yes those give you additional points if you have more cores. Games however are much harder to program to support those additional cores.

About the RAM: I'd just get some DDR2-800 with good timings at 1.8V. Here's an example:
http://www.newegg.com/Product/Product.aspx?Item=N82E16820231209


a b à CPUs
December 28, 2008 3:03:20 PM

^+1 for the GSkill PI.
December 28, 2008 7:06:50 PM

In gaming currently (with allot of lack in support for multi core), the CPU clock speed in all cases will be the bottle neck. On that note, a high clockspeed intel dual or quad would be better.

Tom's article
a b à CPUs
December 29, 2008 3:00:18 AM

If you have a good AM2+ board then you will be able to use an AM3 CPU in it since AM3 basically has the same pin layout with two less pins, thus preventing you from using AM2 CPUs in AM3 boards. It really depends on the games you want to play. The Phenoms are faster than the older AMDs clock for clock, but of course they are clocked much lower and don't overclock as well so it will come down to if the game has some optimization for more than two cores or not. Legion Hardware has some interesting CPU scaling articles on the 4870X2

http://www.legionhardware.com/document.php?id=770

as well as one on the 280

http://www.legionhardware.com/document.php?id=775

So that you can compare AMD X4s and X2s. Of course you may also notice that the CPU charts on Toms were updated to include Windsor and Brisbane AMD CPUs, even if some of the scores seem a little strange to me. For simply the best bang for the buck I would say go for a 5400 BE (heck they're $66 on newegg) or the 7750BE and overclock whichever one you choose. Personally though if I was going to get something in the next two weeks then I'd get a 9850 BE, but I'd wait till the Phenom IIs come out since I'd be hoping for a better price :) .
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