View Full Version : CPU Bottleneck Question

20-06-2012, 09:39 PM
I'm trying to throw together a cheap 775 socket system for my friend. We are intending on using an ATi 4870 as a graphics card. Buying second hand parts, we can get an e4600 combo about $60 cheaper than getting a e8500 combo (cpu,mobo,gpu).

So I looked here to check the performance difference: http://www.anandtech.com/bench/Product/64?vs=55

Photoshop and what not can be ignored, the only thing that matters is the FPS in games, my question is will the 4870 bottleneck the e8500 into performing equalish to the e4600. Instead of say the e4600 bottlenecking the 4870.

21-06-2012, 11:44 AM
If you're quick you could try for this http://www.trademe.co.nz/computers/components/cpus/intel/auction-484790843.htm

As for the question, the result will be mixed. Some games will play the same and some will lose some fps. 60 fps is the magic number for silky smooth game play as a rule, anything above that is not really perceptible. Games tend to be playable from 30fps upwards.
The 775 CPU of choice for games for a long time was the e6750 which I had and it was awesome. The e8500 and 8600 later took over as the most popular. The e4xxx series didn't really feature much in gaming builds but it's powerful enough to handle most of them.
A friend of mine was still gaming on an Athlon x2 5200+ and a HD4850 until Rage came out (single digit fps ouch!) it played most games. He got lucky with a phenom II x3 720 on trademe and upgraded, still using the HD4850 and playing Rage, Skyrim, Diablo3, etc very well (1440x900 monitor doesn't hurt)

I don't like the way people say GPU's or CPU's bottleneck each other because to me it's not exactly true (I think maybe I'm just looking at it differently). For any given game there is a certain minimum amount of GPU and CPU power required to hit 60 fps. If either component is a bit underpowered yes it will drop the fps and is therefore the bottleneck, but to me it's bottlenecking the whole system and not just the one other component - e.g. I would say a slow CPU is a bottleneck, but I wouldn't describe it as bottlenecking the GPU. Some games are very dependant on one or the other, so you can benefit from say a slow dual core CPU and a very powerful graphics card without noticing any bottlenecks in certain games.

Edit: maybe refer to this chart http://www.tomshardware.com/reviews/gaming-cpu-review-overclock,3106-5.html
I refer people to Tom's a lot, not as much detailed comparisons as anandtech but a good general overview.

21-06-2012, 11:47 AM
E4600 has only 1MB cache per core as compared to 3MB per core on the E8500. Speed doesn't matter as a E4600 is pretty grunty enough, but as a game will be playing with RAM a lot, cache matters. My recommendation is to go for E8500 solely because of more cache

21-06-2012, 11:51 AM
Another one to consider http://www.trademe.co.nz/computers/components/cpus/intel/auction-486124345.htm