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Kenny
27-03-2008, 04:29 PM
I'm having a bit of an issue I've been wondering about with my ram frequency.. For some reason it's stuck at 333 ( 332.8 ) MHz.

The ram chipset is supposed to be 800, and the motherboard supports 800, but it just won't go above 333..
I've checked the BIOS settings, and it's set to auto, I've tried swapping the chipset between single and dual, to no effect..

Anyone with any idea about hardware that could tell me why this is happening?

Arthran
27-03-2008, 04:31 PM
what ram is it?

Kenny
27-03-2008, 04:35 PM
Kingston ValueR. DDR2 PC6400 4096MB CL5 (Although I had the same problem with my old corsair 2 GB chipset, which was 667 MHz)

Oogie
27-03-2008, 05:45 PM
Kenny,http://icanhascheezburger.files.wordpress.com/2008/03/funny-pictures-computer-more-rams-field.jpg

Harr
28-03-2008, 12:10 AM
Sounds like its linked to FSB. Try to see in BIOS memory/ram section somewhere if you can change that linked to unlinked.

Kenny
28-03-2008, 04:57 AM
I can't. Most of the settings are just Auto/Manual, and I have everything set to auto. Don't see anything like FSB..

Kinshara
28-03-2008, 07:48 AM
Well, (I think) part of the answer lies in the fact that it's DDR style RAM, which sends out two data transfers per clock pulse(one on the rising edge, one on the falling); DDR2 doubled the bus speed relative to the dram chip speed, so for your 6400 DIMMs the bus is running at 400MHz(with 2 transfer per clock, so effective 800) while the drams are at 200.

http://www.jedec.org/download/search/JESD79-2C.pdf gives a timing diagram if you're interested(page 29, figure 29 -- 4 transfers from drams across 2 dram cycles, and the bus needs to wait for both before starting its own transfers. Bit of a tradeoff in latency.)

For the bus being 333 rather than 400, though... is this an intel or amd system? (And which model is it?)

Kenny
28-03-2008, 09:00 AM
I've been looking into the whole timing table myself.
http://i28.tinypic.com/i23egw.jpg
This means that there's 3 dram cycles, or?

Also, it's Intel Core Duo E6700

Kinshara
28-03-2008, 09:21 AM
No, the number of cycles remains the same; wikipedia has a decent table here http://en.wikipedia.org/wiki/DDR2_SDRAM

The bus frequency is always twice the dram cell frequency -- for a ~333MHz bus, it's ~166 MHz on the cells. The table you posted just lists the timings for a given bus frequency.

If that's a screenshot from your machine, it looks like it's been identified as PC2-5300 rather than PC2-6400, which would explain the bus speed... an E6700 should be able to handle the higher speed fine, so I don't know why it's lower.

http://www.valueram.com/europe/desktop/memory.asp -- may be worth checking the numbers.

*looks a bit further.... ooh*

http://www.valueram.com/europe/datasheets/default.asp -- not sure if the "Intel Validated" table is relevant... those may be separate parts rather than the maximum speeds Intel accept for KVR DIMMs.

Flawless
28-03-2008, 12:15 PM
You do have both sticks in?

Oogie
28-03-2008, 12:22 PM
My LolRAM was ignored :(

Arthran
28-03-2008, 12:25 PM
Kingston ValueR. DDR2 PC6400 4096MB CL5 you said it was, yet your screenshot says that the ram is PC2-5300 which runs at 333MHz. so maybe you've been sent the wrong ram and its actually "working as intended"?

Chopper
28-03-2008, 12:30 PM
Dunno if this is relevant...

If it's dual-channel RAM, 2 sticks going into 2 of 4 slots, then the sticks need to be inserted in the paired slots.

The slots are usually colour-coded to indicate how they're paired, but the "pairing system" and colour coding isn't always consistent between different board manufacturers. Check your motherboard manual.

Courtesy of a quick google, this article might be useful:
http://www.hardwaresecrets.com/article/133/6

Kenny
28-03-2008, 01:12 PM
Actually I copy pasted the wrong ram, I have the PC2-5300, but it's not supposed to be 333 MHz. As I said I had a corsair set which is 667 MHz before and that was also running at 333.

And I've tried moving the chipset around to no result, Chopper. :(
(oh and of course I have both the chips in :P)

Kinshara
28-03-2008, 02:59 PM
Tis WAI, then. The actual bus speed will be 333MHz, but due to it doubling up transfers it's effectively a 667MHz bus. That's how DDR2 works.

Vegelus
28-03-2008, 04:35 PM
Tis WAI, then. The actual bus speed will be 333MHz, but due to it doubling up transfers it's effectively a 667MHz bus. That's how DDR works.
Corrected, DDR SDRAM (Double Data Rate Synchronous Dynamic Random Access Memory).

Gwynin
28-03-2008, 04:37 PM
My LolRAM was ignored :(


Its a good thing tbh, just proves that my suggestion for a technical forum has ended with a very constructive forum section :)

Kinshara
28-03-2008, 04:56 PM
Corrected, DDR SDRAM (Double Data Rate Synchronous Dynamic Random Access Memory).

Well, yeah... I did say DDR style in my first post -- kinda meant it in the general sense :)

But DDR(1) topped out at 266MHz dram/bus speed, whereas DDR2 continued beyond that by separating dram cell speed from the bus speed. So Kenny's RAM will have a ~166MHz dram speed, ~333MHz bus speed, and ~667MHz effective speed, at least in terms of bandwidth.

Tis rambus's new stuff that's crazy, though... 32 transfers/clock.

Oogie
28-03-2008, 05:07 PM
Its a good thing tbh, just proves that my suggestion for a technical forum has ended with a very constructive forum section :)

Good point :)

Borwin
28-03-2008, 05:08 PM
DDR = "two clocks" per clock..
clock = 333
DDR makes this 667 MHz <- some bioses lists this value, therefore the confusion
SDRAM memory bus is 64 bits wide = 8 bytes
667 x 8 = 5336 = PC5300