Question about DDR2 Memory

Apologising in advance if this is long. Sorry.

Ok, so I bought my computer 2 years ago and some extra memory for it to give me a total of 4.5 gig. When I upgraded to windows 7 64 bit, I had to take out 3 sticks, which left me with my 2 gig stick left in. I decided to get more memory and bought another 2 gig ddr2 with the specs of the sticks I took out, which was 533 Mhz. I found out when searching something else out in my bios, that my 2 gig stick that was inside was a 667 and not a 533. My question is....will having a 667 and a 533 sticks in my computer, with one slot in between them empty, hurt my computer or cause a bad enough slow down that I should stick with whichever is actually better? Or will it be good till I can buy more of whichever is better. And which IS better, while I'm at it?

 

Apparently, most DDR2 chips on the market support operation at CAS 3, 4, and 5. This means the slower rated 533MHz, CAS 4 stick should work fine alongside the 667MHz stick
typically
533MHz: runs at 4-3-3-12
667MHz:runs at 5-4-4-15
DDR2-667 -if you install it along with DDR2-533, will run at DDR2-533 speed anyway. So if you install 533 , the system will run at 533 clock rate, ( this is probably about a single percentage slower).but the extra ram will give better overall performance.
Mixing different speeds of DDR could cause instability,- memory not getting read, system crashes, but generally because the bios will run it at the slowest speed, it will work o.k
Advice ? Use identical sticks of the same 667 , especially if running dual channel, as it will not get the benifit of dual channel performance.

 

So, I'll be good, until I can get another stick of 667 or two, then. That's good to know.

 

They dont have to be identical brand but identical spec. I have 3 Crucial sticks and 1 Kingston and they are fine.

 

No they don't have to be agreed

but its better to have the same ram in all the slots so that the timeing is the same.

 

Identical spec, how? I know both sticks should be PC2 4200 DDR2 2 gig memory sticks, just one is a 667, and the new one is a 533. I got the 533, cause I thought the 667 was a 533, but found out otherwise when looking for something else when it was too late to change the order.

 

welp just found something that told me more about my current ddr2, apparently it's NOT a pc2 4200, its a 5300 @_@. So more than likely i bought that other for nothing...wasted 50 bucks.

 

This might help explain it

http://www.crucial.com/kb/answer.aspx?qid=4073
PC2-4200 (DDR2-533), PC2-5300 (DDR2-667), PC2-6400 (DDR2-800), and PC2-8500 (DDR2-1066) memory are all types of Double Data Rate, second-generation SDRAM, usually referred to as DDR2. The varying numbers refer to the different speeds of memory your computer was designed for.

Let's take a look at PC2-4200 (DDR2-533) to break it down simply.

PC2-4200 (DDR2-533) refers to the bandwidth of the memory. A PC2-4200 module has the bandwidth of 4.2 GB/sec; therefore, it is referred to as PC2-4200.

DDR2-533 refers to the effective front-side bus speed of your system. While your DDR2 system or motherboard may operate a 266MHz front-side bus, its effective front-side bus speed is 533MHz because DDR2 effectively doubles the amount of data transferred per cycle that a non-DDR2 system would.

The same holds true for PC2-5300 (DDR2-667), which has a bandwidth of 5.3GB/sec and is designed for use in systems and motherboards that require a 333MHz front-side bus, with an effective front-side bus speed of 667MHz. And the same holds true for PC2-6400 (DDR2-800), which has a bandwidth of 6.4GB/sec and is designed for use in systems and motherboards that require a 400MHz front-side bus, with an effective front-side bus speed of 800MHz.

Though DDR2 memory was designed to be backward-compatible (meaning you can use PC2-5300 module in a computer designed to use PC2-4200, or vice-versa), we always recommend that you use the Crucial Memory Advisor tool to find exactly the right memory for your computer.

PC 5300 would be better then the 4200