Mem selection: CAS Latency 4-4-4-15 vs 5-5-5-15

[MplsBob]

I have no previous experience with DDR2 and almost none overclocking.

I want to wring the upper limits out of my E6700 without making either a dumb choice or spending money on inconsequential features.

Some chips are rated at the desired PC2-8500 with a CAS Latency 4-4-4-15 and others with a CAS Latency 5-5-5-15.

As an after thought, is PC2-8500 a good choice in this situation?

 

[Baked]

Lower timing speeds up calculation, as evidence by running SuperPi. Faster timing also means your RAM has more headroom for overclocking, meaning when you lower the timing, it can overclock higher.

 

[tyler811]

Lower is better

 

[Skeeedunt]

Tighter timings are about the least bang-for-your-buck thing out there. The money would usually be better spent on just about any other component in the system.

 

[MplsBob]

You have denigrated my initial message, but none of you have made any useful contributions, like what memory would make better sense. Surely there is something between engraving data on stone tablets and infinite speed.

Please, some responses with more detail.


edit-----------------
Baked made a useful reply in that he explained the value of latency.

 

[sygyzy]

What is that last latency value for? I started seeing this with DDR2.

 

[theprodigalrebel]

Don't go for any DDR2-1000+ rated RAM. They are priced way too expensive, usually $400+.

Most DDR2-800 RAM rated at 4-4-4-12 are overclocking very well (like the ones from Corsair, Patriot and G.Skill....lots of them are going close to DDR2-1100 with 5-5-5 timings...sometimes DDR2-1000 with 4-4-4-12 and more voltage). These are all around $225-275.

DDR2-800 RAM rated at 5-5-5-15 will save you around $50 (on average) from the above, but they usually have very little headroom.

There were a few articles on Firingsquad.com and others a month ago, detailing the advantages of bandwidth/timings with Core 2 Duos. Most of it was almost negligible. Since you already have a high-multiplier chip, you won't need insane FSBs to reach your max overclock like the E6300/E6400 guys do.

EVEN if you can hit that fabled 4GHz with your E6700, you can do it with plain vanilla DDR2-800 running 1:1 (or DDR2-1000 with the 4:5 DDR2-667 divider). And going from 800MHz @ 5-5-5-15 to 1000MHz @ 4-4-4-12 might give you 0-5% increases depending on the application. It's all relative....what price/performance means to you....

 

[theprodigalrebel]

Originally posted by: sygyzy
What is that last latency value for? I started seeing this with DDR2.

You mean Cycle Time(tRAS)? It's there with DDR memory too. (2-2-2-5, 3-4-4-8 etc.)

 

[Skeeedunt]

Originally posted by: MplsBob
You have denigrated my initial message, but none of you have made any useful contributions, like what memory would make better sense. Surely there is something between engraving data on stone tablets and infinite speed.

Sorry, didn't mean to come off as a dick. I just meant that I wouldn't spend a dime on tighter timings unless everything else on the system was already maxed out. DDR2 800 is a good choice for overclocking, DDR2 533 (stock for c2d) if you're not.

 

[Howard]

Originally posted by: MplsBob
You have denigrated my initial message, but none of you have made any useful contributions, like what memory would make better sense. Surely there is something between engraving data on stone tablets and infinite speed.

Please, some responses with more detail.


edit-----------------
Baked made a useful reply in that he explained the value of latency.

Forgive us, master.