CL2 vs CL2.5

[akshtray]

Hello:

Is there anyway I can get a CL2 memory module to work on a motherboard which my PC company says supports CL2.5 only.

Thanks
akshtray

 

[Jadow]

yeah, just set it to 2.5 in teh bios. That's kinda odd that a mobo says it only supports 2.5 though.

 

[akshtray]

thanks for the quick response ..

the only setting for RAM i know is the DRAM speed setting which says:

1. By SPD, 200, 266, 333 as the only options.

thanks
akshtray

 

[Acanthus]

if there are no cas settings, there may be a timings tab? itll have something to effect of settings like safe, normal, fast, ultra. Normally those play with CAS, RAS to CAS, precharge, and command times.

 

[Jadow]

some OEM computers really have skimped down bioses. Have you actually tried this memory adn it doesnt work?

 

[capricorn]

If you have your BIOS set to using SPD for your memory, you generally can't set any of the timing parameters. Go off SPD to the actual speed of your memory (e.g., 333 MHz) and you should be able to set the CAS level. That's how it works on ASUS, Gigabyte, etc motherboards. If this is a Dell, HP/Compaq motherboard, all bets are off. They seem to like to whack their BIOS's down to nothing.

You're basically asking the memory to run at a slower speed than the fastest it's rated for, so I'd be surprized if you couldn't just put it in and have it work.

-cap

 

[akshtray]

Hi:

i have 2 pc2700 512MB .. and 1 pc2100 256MB one ..

the pc boots up fine when the pc2700 is paired with the pc2100 ... but when the 2 pc2700's are paired with each other the computer does not boot up .. infact it does not boot up if all i have is just one of the pc2700 calling the pc company did not help much as they insist that their board supports pc2700 memory .. to be honest i did check up on the sis 648 board and according to official documentation it should support pc2700 ..

the problem with setting the SPD to 333 MHz is that if I have the pc2700 chip(s) in .. the computer does not even boot enough so that i can go into the bios .. this is basically what has me going in a loop as to how to set the spd to 333 or even change the CAS or any other setting ..

akshtray

 

[akshtray]

ummm .. still waiting for any more suggestions ... ..

mainly i want to hear someone say .. CL2 should be able to run on a MB with CL2.5 .. ..

akshtray

 

[ElFenix]

CL2 will no doubt run set at 2.5. CL2 is the lowest latency its rated for, it will run at any higher latency as well.

the SPD is an identifier string coded into the memory that tells the board what the default settings for the memory are.

 

[Lonyo]

Boot up with a PC2100 and a PC2700, don't set by SPD, set CAS to 2.5, then turn off, stick in the 2 PC2700's and reboot.

If you have it set by SPD and use the 2 PC2700's, then it'll try for CAS 2, so you need to set it off SPD when you want to use the two PC2700 modules.

It works with a PC2100 and PC2700 because I guess the 2100 is a CAS 2.5 module, so the mobo sets for the worst SPD setting, which would be 2.5.

 

[akshtray]

thanks guys ..

i feel happier now .. ..

one last question before i actually go and try this .. when i turn By SPD off .. should i change it to 266 or 333 .. also .. which area of the BIOS do you think will have settings for changing CAS to 2.5 ..

thanks a bunch
akshtray

 

[akshtray]

nope .. did not see any setting fro RAM other than changing the Speed to By SPD, 200, 266 or 333. I have given up on the RAM. I am simply going to return it and get RAM with a value of CL2.5 and CAS2.5

THanks to you all anyway .. i appreciate it ..

akshtray

 

[RyanVM]

Some of the newer low latency DDR memory is programmed to CAS2 on the onboard SPD chip (amongst many other low timings). Combining one of these sticks with the "By SPD" setting in your BIOS *should* work for enabling CAS2 on your board.

 

[akshtray]

I actually have 2 sticks of 512 PC2700 and 1 old stick of 256MB PC2100 (which came with the PC). However, it does not matter as to what combination I use when I use any new stick with the old stick. It works. They problem is only when I use the 2 new sticks together. I am thinking that maybe my motherboard for whatever reason cannot handle the PC2700 RAM with a CL2.0.

i have tried using the old and the new stick together which works. I changed the BySPD to 266 (which should work) and then rebooted with the 2 new sticks and dont work. Its just futile .. i give up ..

So most likely I will return the RAM tomorrow unless any other suggestions work.

Thanks
akshtray