Compaq Memory upgrade - Best Bang for the Buck

Upgrading kids HP/Compaq via Cruial web site.
With DDR2 memory sticks at bargain prices, want to install 2GB kit (1GBx2). Currently running (2x) 256MB - DDR2-533

Have narrowed it down to ...
2GB kit (1GBx2), 240-pin DIMM, DDR2 PC2-4200
2GB kit (1GBx2), 240-pin DIMM, DDR2 PC2-5300

My confusion is rated memory speed versus CL rating.
PC2-4200 / DDR2-533 has a rating of CL=4
PC2-5300 / DDR2-667 has a rating of CL=5

How does the memory speed 533 or 667 interplay with CL (clock cycles, lower the better, BUT at initial burst speed burst speed, then neutral).

Possible some helpful information
Understanding spec's - Crucial - Basic Guide to Memory.

 

Hi Dennis,
I can only speak generally, because I only need to know generally about it.

Your current RAM is DDR2-533, which, if matched to the system, means the optimum FSB for the machine is 533Mhz. If you buy DDR2-667, it will run at 533Mhz unless you start overclocking.

DDR2-667 is compatible with your motherboard, you may as well get it for a few dollars extra. It might come in handy if need to replace the motherboard and find the higher speed can then be utilized (depending on if it is tied to the FSB of the CPU).

From my understanding, if the DDR2-667 runs at a lower FSB the CL should match that of the standard rated modules. In other words, if the DDR2-667 runs at 533Mhz, you should find the CL is adjusted to 4.

Matt

 

Thank you Matt - most appreciated.
I was suspicious 677 chip would fall back to mobo default of 533.... and this is why (I'm assuming) is why Crucial had it on the compatibility list. The pleasant surprise is CL also reverts back to 4. As far as OC'ing this computer, BIOS is locked up. About all BIOS lets you change is Boot Order and enable/disable onboard devices. Now I'm sure their is BIOS flashes which would accommodate OC'ing, but this computer/hardware's purpose is to pleasantly surf the web and keep the kids and their media/devices in constant tune-age. It will be interesting to see what performance does moving from 512MB to 2GB... keeping in mind, 256MB onboard video card is shared memory.
Thanks Matt

 

Thread update - Crucial 2GB kit (1GBx2), 240-pin DIMM, DDR2 PC2-5300 / DDR2-667 arrived.

Removed power cord - pushed Power ON button to flush residual, opened-up box. Got my cleaning tools out and cleaned her up. Removed old sticks, installed new sticks. With fingers crossed, powered up and computer booted with no problems. Was worried about OEM's fussy requirements per proper memory and / or a DOA stick. Loaded SWI and CPUz and both report each 1GB stick is recognized and running at 333/677 and CAS is stated at 5... cool. See the following SWI report ...

The only adjustment I've made so far was to Pagefile. I previously had it set to custom (when running 512MB), but now have it set to XP-Managed. What have I noticed so far ... dramatic reduction in HDD activity and duration. Also nice screen pop when loading programs. Kids normal active running are Firefox / web games, MSN 8.1 Live Messenger, while listening to music via local network. I'm happy, kids happy. With DDR2 memory at rock bottom pricing, inexpensive "Upgrade" for our low-end system.

 

Glad to see everyone is happy, including the computer and your wallet

PS: As you were saying, DDR2 has a good price at the moment. DDR3 will "ramped up ".