Memory timings?

Half Evil

Golden Master
Messages
16,076
Will someone just explain this to me. Because its like.. 2.5-3-3-7. (example). But what are they for, what do they tell you. At the moment, they mean nothing to me, lol..
 

The Amish Kid

Fully Optimized
Messages
2,059
Well the main one you should be concerned with is the first one. That's your CAS latency. The lower the better.
 

MikeReiner

Golden Master
Messages
5,055
yeah, supposedly 2.0 is really high performance and constitutes spending an extra $50.

personally, I think 2.5 is perfectly fine.

Amish kid has 1,111 posts :p
 

G35x

Golden Master
Messages
5,474
Yeah i have 2.5 i dont really think 2 is all the great its not that big of a difference from 2.0-2.5
 

Flipper

BSOD
Messages
246
It is a major difference between DDR and DDR2.

Socket AM2 (AMD's Upcoming socket) will use DDR2 RAM on it's motherboards, since DDR2 runs at faster clock speeds, there is of course a down point. The cas latency, The cas latency on DDR2 RAM is MUCH higher than DDR, to define cas latency it is basically measured in nanoseconds the amount of delay between running applications, thats why the lower the CL the faster you perform.
Technical Definition:
CAS latency is determined by dividing the column access time by the memory clock cycle time. Simply put, the CAS latency is the number of clock cycles it takes the memory to respond to an operation request. Lower CAS latency, therefore, will normally give slightly better performance than higher CAS latency. The default CAS latency for SDRAM is 3 and for DDR is 2.5. The lowest possible CAS latency is 2.


Alright now for the example between DDR and DDR2 RAM's speed compared to CL:

See DDR2:


Notice on one of those timings it is 4-4-4-12! So I guess it's safe to assume the average DDR2 Cas latency is 4.

Now on to DDR:


Now you can see the average CL for DDR RAM is around 2.5-3 going as low as 2.

As I've shown there are some advantages to both....wow...I just rambled and spent way too much time on one post that wasn't even relevant to the topic, I feel like a high school teacher.
 

MikeReiner

Golden Master
Messages
5,055
Haha, it's good information for those who do not know much on the subject though. so don't feel too bad. :)
 
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