Computing.Net > Forums > CPUs/Overclocking > Ram FSB question

Computer Problems? Computing.Net has over 1,000,000 posts about all things technology related! Over 90% answered within 24 hours! Click here to start participating now! Also, be sure to check out the New User Guide.

Ram FSB question

Reply to Message Icon

Name: protohunter
Date: November 11, 2007 at 03:59:06 Pacific
OS: XP
CPU/Ram: Pentium D 3.0GHz/1GB
Comment:

I have a question, I have a Pentium D said to run on an 800mhz fsb however my ram is DDR2 PC2-4300 rated at 533mhz. Does this mean that my cpu is not running at the right fsb also?

Sorry if I sound like a noob I just don't understand DDR that much. I'm too used to the old P3 days where the cpu fsb and ram ran at the same speed.



Sponsored Link
Ads by Google

Response Number 1
Name: jam
Date: November 11, 2007 at 06:31:28 Pacific
Reply:

"I'm too used to the old P3 days where the cpu fsb and ram ran at the same speed"

The CPU & RAM should run at the same frequency. Your Pentium D actually runs at 200MHz, not 800MHz. 800MHz is the effective speed due to "quad pumping". If you check the settings, you'll find your CPU is clocked at 15 x 200MHz.

Your DDR2-533 RAM actually runs at 266MHz, not 533MHz, with 533MHz being the effective speed due to "double pumping".

In other words, your RAM frequency is running faster than your CPU frequency. Your current CPU:DRAM ratio is 200:266, or 3:4. A 1:1 ratio is considered optimal.


0

Response Number 2
Name: protohunter
Date: November 11, 2007 at 11:43:20 Pacific
Reply:

Ok thanks for the info, what kind of ram would I need for it to run on a 1:1 ratio?

And also this mobo can support Core 2 duos however will the ram currently installed support the Core 2 duos higher bus speed?


0

Response Number 3
Name: jam
Date: November 11, 2007 at 12:40:01 Pacific
Reply:

"what kind of ram would I need for it to run on a 1:1 ratio?"

Either change the memory setting in the BIOS to DDR400, or just leave is it is & don't worry about it.

The RAM you have will support a 1066MHz FSB (266MHz frequency) Core 2 Duo. Does your board support 1066MHz FSB CPUs?


0

Response Number 4
Name: protohunter
Date: November 11, 2007 at 13:16:32 Pacific
Reply:

Well I can't change anything like that in the bios because I have a Comcrap computer, however I did read the manual and it said that it does support Core 2 duo Cpus.


0

Response Number 5
Name: Outlander
Date: November 13, 2007 at 07:53:41 Pacific
Reply:

Changing the ram to PC3200 will only serve to downgrade performance.

If you want an effective 1:1, than its 800mhz cpu FSB to DDR2 800(6400).

If you want proof, run any memory benchmark(memtest x86, sisoft sandra) and you will see a huge decrease in ram speed going from 533 to 400 DDR2.


0

Related Posts

See More



Response Number 6
Name: digger95
Date: November 14, 2007 at 09:49:49 Pacific
Reply:

I sometimes wonder if this is why I never quite got the speed I expected out of my new machine (new in 2005 anyway).

HP shipped it from the factory with PC3200 memory that gives me an fsb:dram ratio of 4:5. It's a moot point now because I'm not about to change out the modules, but I have often wondered if my performance suffered slightly as a result.

I realize these manufacturers throw in whatever bulk memory is cheapest at the time and I've never had a problem with the machine. But I've often felt it should be running faster.

Oh well!

Dig


Slackware Linux Enthusiast


0

Sponsored Link
Ads by Google
Reply to Message Icon






Post Locked

This post is quite old and has been locked from receiving new replies. Please create a new posting instead.


Go to CPUs/Overclocking Forum Home


Sponsored links

Ads by Google


Results for: Ram FSB question

cpu/ram fsb www.computing.net/answers/cpus/cpuram-fsb/10517.html

DDR RAM Frequency Question www.computing.net/answers/cpus/ddr-ram-frequency-question/6253.html

Overclocking FSB question www.computing.net/answers/cpus/overclocking-fsb-question/6962.html