Memory Speed/Cas Latency Question

[iluvdolphin]

Yes, another RAM question. I saw in Ketchup's OC'ing guide that he said:

Quote:Contrary to popular belief, anything above DDR2 800 with cl5 is going to make a very very small impact on performance in games. It will make a decent improvement in synthetic benchmarks but we don't care about those. All we care about is CPU operations per second for Dolphin.

Is this true? I thought i# series CPUs were better than AMD in part because of their memory controller (besides architecture) and that better memory was better in Dolphin. Ketchup makes it sound like memory makes almost no difference at all and I find this hard to believe from other things I've read on here.

How does cas latency and memory speed actually affect performance in Dolphin? I'm especially interested in memory timings (e.g. cas 7 vs cas 8 vs cas 9) and better timings vs higher clocks. Is it only EFB copy to RAM that needs better memory?

[obscured]

The I series is better with memory because they moved the memory controller on to the cpu die (less latency), ddr3, and tri channel does help but in the end raw cpu speed usually does the most impact on gaming. Memory can only do so much. I personally would go with tighter timings with decent clocks. Dolphin doesn't use much memory for a system built to today's standards.

[NaturalViolence]

Quote:Is it only EFB copy to RAM that needs better memory?

Basically.

Quote:How does cas latency and memory speed actually affect performance in Dolphin?

Depends. If you are using a core2 duo/quad it won't affect actual memory bandwidth much because the FSB will bottleneck it. Assuming you get rid of that bottleneck...well that depends on if dolphin does a lot of random read/write or sequential read/write. I believe dolphin does a lot more sequential read/write but I'm not totally sure. For random read/write lower latency is preferable to higher clock rate while with sequential read/write higher clock rate is preferential to lower latency. 99% of the time higher memory clock rates have a greater impact than lower latency.

Quote:Ketchup makes it sound like memory makes almost no difference at all and I find this hard to believe from other things I've read on here.

When did it he write this? It might be out of date and his statement might have been true at the time he wrote it.

When you are talking about pc games he is correct. Anything past ddr2 800 is pointless for pc games since they don't need very much memory bandwidth, dolphin on the other hand does constant fb read/writes for efb emulation if efb to ram is used.

[iluvdolphin]

(11-20-2010, 05:07 PM)NaturalViolence Wrote:

Quote:Is it only EFB copy to RAM that needs better memory?

Basically.

Quote:How does cas latency and memory speed actually affect performance in Dolphin?

Depends. If you are using a core2 duo/quad it won't affect actual memory bandwidth much because the FSB will bottleneck it. Assuming you get rid of that bottleneck...well that depends on if dolphin does a lot of random read/write or sequential read/write. I believe dolphin does a lot more sequential read/write but I'm not totally sure. For random read/write lower latency is preferable to higher clock rate while with sequential read/write higher clock rate is preferential to lower latency. 99% of the time higher memory clock rates have a greater impact than lower latency.

Quote:Ketchup makes it sound like memory makes almost no difference at all and I find this hard to believe from other things I've read on here.

When did it he write this? It might be out of date and his statement might have been true at the time he wrote it.

When you are talking about pc games he is correct. Anything past ddr2 800 is pointless for pc games since they don't need very much memory bandwidth, dolphin on the other hand does constant fb read/writes for efb emulation if efb to ram is used.

Thanks for the replies, guys.

Here's the link:

http://forums.dolphin-emu.org/thread-11895.html

The date is 09-03-2010.

[NaturalViolence]

Nope I guess he's just uninformed/didn't actually fully test it himself.