Ram timing and basic thoughts

i just have a simple question about RAM.

would someone please explain to me what timing mean in ram like, 7-7-7 24 or whatever.

just started to get involved in computer parts (been working with programs till now) and i just want to get to know the parts better.

so i would like to know what that means and how do you check what the timing on your ram is and its mhz frequency.


this is the pc i have as of now tell me your thoughts. bare in mind that this is my first build

I7 920
G.SKILL 6GB (3 x 2GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Triple Channel Kit
Two Caviar Blacks in raid 0
GTX 280
EVGA Micro ATX X58 SLI/Crossfire
Antec 300
Coolermaster 212 Plus
Corsair 650w

please tell me your thoughts

Thanks again to all

RAM timings, aka latencies, is a measure of how long it takes for the memory to relay information back to the CPU. The higher or looser the timings, the worse, as it takes longer for the RAM to relay information to the CPU, and thus, slows down the performance of your PC. Normally the lower the latencies, the more expensive the RAM. Also, tighter/lower memory timings provide a more noticeable performance boost than higher speed RAM.

Each of those numbers stands for a different parameter:

What happens when accessing memory:

Step 1. tRCD (RAS to CAS Delay) - The row is selected by the Memory Controller. A typical number for DDR3 is 7

2. CAS (Column Address Strobe) - The Memory Controller selects the column and now the ROW is ACTIVE, and the READ COMMAND is sent.

3. Data is sent to the DQ pins after CAS delay.

4. tRAS (Row address Strobe): The module waits a certain period of time for the data to be active. Call it 24 for typical DDR3.

5. tRP (RAS precharge) 2 cycles, The Memory Controller DEACTIVATES the row. 7 again.

6. Memory Cycle repeats as requested by the Memory Controller.

The timings I mentioned above are represented as: 7-7-7-24 1T (CAS, tRCD, tRP, tRAS) The 1T is the command rate: This is how long instructions are presented to the memory modules. 1T means instructions are presented for only 1 cycle. 2T is 2 cycles.


Since these numbers represent how many clock cycles it takes to perform the action, larger numbers are slower. But at the same time, larger numbers allow more time for the function to actually complete: So they tend to be more stable.




Regarding what counts as good/fast timings versus slow timings; it depends on the type of memory. For old school DDR memory, 2 and 3 are typical timings. For DDR2 you're more likely to see 4 to 8. For DDR3?? 7 and looser. The reason for this is that - as clock speeds increase - it becomes easier for a function to not complete in the shorter timespan. So timings have to be loosened to ensure the given functions can complete reliably.

Your build looks fine

Okay so im looking at my next build and came to realize that the timing sucks
http://www.newegg.com/Product/Prod [...] 6820231225

its 9-9-9-24

can someone tell me if they have a better ram in mind ?

Sorry for hijacking this thread, but I'm researching RAM for an i7 build myself...

My future rig: (Digital Audio Workstation use only)
i7, Win7Home-64bit
MOBO: ASUS P6T Deluxe V2 [memory standard: 1600(o.c.), 1333]
PS: Corsair TX650, Case: Antec P180, Thermalright Ultra120Extreme1366
HIS H467PR1GH Radeon HD 4670 1GB PCI-e(for dual monitors, & Maxivista+networked 2nd PC for third monitor)

No plans to overclock.

Want 6GB DDR3 triple channel RAM. Looking at G.Skill.

Would it be better to get the 1600 with 9-9-9-24 or the 1333 with 7-7-7-18?

They are both essentially the same price (only $10 difference).
The 1600 memory with the 9-9-9-24 is on ASUS's QVL. The other isn't. (QVL updated Oct2009)
Which would be the choice you'd make?

Also, everthing look ok with this rig? I've been scouring the forums/internet... and come up with this so far. Any suggestions greatly appreciated.

I'd like to point out that it will take a very good system benchmark to distinguish between 8-8-8-24 and 9-9-9-24 RAM.

Don't obsess.