[bundee1]

Im fixing a friends computer and I asked about DDR 2700 RAM at 266 mhz and the guy at Compusa said they only make 2700 at 333mhz not 266mhz.

Thanks for helping out.

 

[Sinbios]

DDR2700 = 333Mhz.

 

[aphex944]

The "PCxxxx" numbers are directly related to the speed(mHz) of the RAM.

PC2100 = DDR 266
PC2700 = DDR 333
PC3200 = DDR 400

Higher speed memory will run at lower speeds, i.e., you can run a PC2700 module(which is DDR 333mHz) at 266mHz.

 

[bundee1]

When I go into setup before the Windows logo pops up it says:

slot 1 2700 DDR 512 mb (this is the 333mhz for sure)
slot 2 2700 DDR 256mb (not sure but I think its 266mhz)
266 mhz

BTW I installed it and it is running a lot faster. It seems to me that the 512mb 333mhz alone is running faster than both chips installed. Could this be right or am I imagining things?

 

[akwok]

Both chips are running at DDR266.

Might I ask what CPU you are running? If it is a P4 533FSB version, then this is the highest you can push it without overclocking the CPU.

(The speed is probably due to the extra memory)

 

[Shayla]

I've seen where mismatched latencies can be bad... but there should be enough leeway to make them live happily together.

 

[akwok]

Mismatched latencies aren't usually a big issue, as the most lax timings can be used.

 

[bundee1]

Its a P4 2.4ghz. Should it run faster if I used the 512mb 333mhz ram alone instead of paired with the 256mb 266mhz stick?

 

[Mr.Radar]

The speed of most CPUs is determined by this formula: FSB speed x CPU multiplier. On modern CPUs the multiplier is fixed so you can't change that. The FSB speed, however, is not. For Intel CPUs that are "Quad Pumped," like your P4 2.4, you need to halve their advertised FSB to get the real FSB they should be using. For your P4 2.4 that is 266 MHz. So to find the multiplier you take the total speed (2400 MHz) and divide it by the FSB (266 MHz) and you get 9.0. So if you ran the FSB at 333 MHz you'd get 333 x 9.0 = 3.0 GHz which will definately be faster. Running a CPU at a speed faster than what it was rated at is called overclocking.

Overclocking has two major problems: CPUs get hotter as they run faster so you need a cooler that can support the speed you're running at. The stock Intel cooler will probably not cut it for overclocking. Second, a CPU rated to run at 2.4 GHz can have processing errors at 3.0 GHz which are caused by running too fast or too hot. The "too hot" problem can be solved by a new cooler while the "too fast" problem cannot usually be solved (sometimes giving the CPU more voltage can help, but that also causes it to run hotter). CPU manufacturers test all their CPUs to see how fast they can run. They sell the ones that can run fast at higher prices, and the ones that can't run fast without errors at lower prices. Usually after a CPU has been in production for a while they get so good at producing them that they end up making more processors that can run fast than they have a market for so they'll sell the extra fast ones as slow ones. Overclockers usually try to get these chips because they'll run at the higher speeds without any processing errors.

You can usually only tell which kind of chip you have (one that can only run at lower speeds or one that was fast but they sold it as slow) if you test it. A good program for that is Prime95's torture test. This test isn't always accurate though, because if your system is unstable in another way (like your RAM can't run at high speeds or your power supply can't supply enough power) you'll get errors even if its not the CPU's fault.

Some other problems with overclocking is that it will void the warantee on your CPU and it may also decrease the life of it (especially if you crank the voltage up). If you're interested in learning more about overclocking check out this great forum: www.ocforums.com

 

[Sinbios]

...Or you could run your memory out of synch with FSB and bump them to 333Mhz, as they're meant to be.

 

[Shayla]

Running your memory out of sync is NOT a good idea. Performance drops considerably compared to running at a slightly slower FSB to run them in sync. Things have been tuned for years and years for the cache to be used every few clock cycles, and that's where your performance is at. I know newer chipsets support running memory out of sync, but it's probably not a good idea. If it's a 266 mhz FSB, and you have a stick of 333mhz and 266mhz, then just run the 333mhz stick slower than it's rated, and keep everything at 266.

 

[Sinbios]

Quote:

Originally Posted by Ryuichi Running your memory out of sync is NOT a good idea. Performance drops considerably compared to running at a slightly slower FSB to run them in sync. Things have been tuned for years and years for the cache to be used every few clock cycles, and that's where your performance is at. I know newer chipsets support running memory out of sync, but it's probably not a good idea. If it's a 266 mhz FSB, and you have a stick of 333mhz and 266mhz, then just run the 333mhz stick slower than it's rated, and keep everything at 266.

He has two 333Mhz sticks, one is running at 333Mhz and one at 266Mhz. Don't ask me how. Thus is it out of sync already and he could just bump the other stick to 333Mhz.

 

[bundee1]

The one that was already in the PC (256mb) seemed to be running at 266mhz or that is what the blue setup secreen says and the new one (512mb) says 333mhz on the package. I installed both and the pc seemed to run faster with the one 512mb stick than with the 256mb stick +512mb stick.
Any thoughts.

Can a computer designed to run with 2100 DDR 266MHZ ram work with 2700DDR 333MHZ ram?

 

[Reck45]

I know on some mobos, if you are running 2 different speeds of ram, it will automatically default to the speed of the slowest stick. So it's possible that the 333 ram is running at 266 already. If it's not, drop the 333 stick to 266 so you're at 1:1 which is the fastest.

 

[alexik01]

I'd suggest downloading CPU-Z . It will tell you all about what speeds your memory and processor are running at. And a bunch of other stuff too.