"Loosest" DDR2 Timings Possible?

So I have a stick of Corsair VS DDR2-533, 512MB. And I'm confused about latencies. Now, at DDR2-400 speeds, it does 3-3-3-8. At DDR2-533 speeds, it does 4-4-4-12. Makes sense. But I heard on another board at some point that higher numbers on everything aren't always the loosest timings---like that 2-2-2-5 was actually higher latency than 2-2-2-6 (if that isn't true I have a faulty memory...heh, memory!). So I'm wondering the LOOSEST timing possible for my memory. I can do

CAS, #2, #3: 3-5
#4: 5-15

So what is the LOOSEST? Although it occured to me that since I'm doing 1:1 with my Prescott and it's running at DDR2-400 (well 436 but whatever), it would make sense to run it at 4-4-4-12, the latency at which it can run DDR2-533 without issue...but still! The question!

And I wish I could get past a 218MHz FSB. I guess it's my mobo to blame, maybe I should flash the BIOS from 1.4 to 1.5.....

MSI 915P Combo-Fr
Intel 530J 3.0GHz Prescott
512MB CVS DDR2-533

Higher numbers mean you're setting the RAM for looser timings. That will always be true for the settings in question. In case you're confused (I can't tell from your post), looser timings is equivalent to higher latency which means slower RAM and less bandwidth.

There are a couple notable exceptions where tighter timings (lower numbers) don't mean faster RAM. The fourth number in 2-2-2-5 is the tRAS, which controls (as I understand it) the total time allowed for the RAM to make an access. If it can't make the access that fast, that constitutes an error, and it has to try again. If it continually errors at 2-2-2-5, it will take longer to eventually get at the memory data than if it doesn't error at 2-2-2-6.

Also, on nForce2 boards, there is a quirk where tRAS should always be set to 11 for the best performance (so 2-2-2-11 would be the fastest setting).

See more at: http://www.ocforums.com/showthread.php?threadid=257741

Informative post and nice cat . Thanks. I still can't get over this 218MHz barrier .

I am new to Intel myself...I am in the process of putting togehter my first Intel system. However, from the reading I have done...I have gathered that the i915 chipset has a slight problem locking the frequency of the videocard and such. I would doubt that you are OCing your video card running at such a low FSB though. I have also been told that the two main motherboard brands to use for intel systems are Abit and Asus (with DFI in there some place). I would think that it is your motherboard if the memory is rated to do DDR2 533 (266 FSB). It seems like the MSI section here is a little skimpy, but check around and see what you can find out about your board.

Restorer said:

Also, on nForce2 boards, there is a quirk where tRAS should always be set to 11 for the best performance (so 2-2-2-11 would be the fastest setting).

Click to expand...

Is that why Memtest86 failed when my RAM was at 200 mhz on an Asus A7N8X-E Deluxe motherboard I tested last year?

Memtest86 displayed at least 10 errors when using 2.5-3-3-7 and even when at 3-4-4-8!!!

Would have changing the tRAS to 11 make Memtest86 pass?

The RAM, which is 512 MB of Kingston PC2700 DDR SDRAM and has Infineon chips is stable at 195 mhz and lower. If I even went to 196 mhz, Memtest86 would fail with at least 2 errors.

You might try giving the N/B more voltage. Default is 1.5v, but if you have active cooling on the N/B, maybe try 1.7v. Most i915 chipset mobos aren't that good for overclocking and MSI ain't that good either. Combine those two and you have a double whammy.

Heh yes for once I get slammed for being an early adoptor (this was before the i925 was around even).

And to alchemy: Yes, this is DDR2-533, but I dropped it down to DDR2-400 because this memory isn't the best-of-the-best when it comes to OCing (Corsair value), so it, in theory, should be fine at stock voltage (1.8V) through a FSB of 266MHz (that's almost 4GHz there) which I don't seem to be anywhere near reaching. NB voltage stock is 1.55 and I tried 1.65 a while back to no result. I'll try 1.7V with my spare 92mm fan on it some time.

With a little extra RAM voltage, you might improve timings. I have 3 pairs of DDR2 RAM and they all seem to have no problem running 2.0v as long as you have decent case ventilation. My OCZ actually is guaranteed to handle 2.2v.