mismatching mem

vegas_sig

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Feb 9, 2007
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I am building a low end gaming system from scraps I have laying around and wondered what the impact to mixing RAM on one system...

ie 2 x 512 2200 and 2 x 512 3200 (diff brands as well).

Will this work or will I have issues?

Thanks in advance.
 

rockyjohn

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They may work if the timings are the same - providing of course that each set alone is compatible with the system.
The higher memory will step down to the speed of the lower. Check your manual so you put each pair on the correct slots.
 

mikeny

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Don't mix speeds. Your system will start to cough, hickup, sneeze, and eventually faint (shut off and restart). I had ddr2-533 mixed with ddr2-675 and thats what happened, my system became very unstable. Both were by corsair. I heard never, never, never do this while mixing companies ie corsair and OCZ.

Corsair doesnt recomment you mix speed period. While you can change the timing but they said its strongly not advised. This was from an email they replied to what happened when I mixed speeds.
 

rockyjohn

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Mixing speed in and off itself, is not a big deal, especially for units close in speed. I purchased a system with 2 x 256MB 400 MHz memory.
I wanted to immediately upgrade to by adding 2 x 512MB and then later install another 2 x 512MB replacing the first - for a total then of 2 GB.
The MB could use either 400MHz or 533MHz.
Since I wanted the faster memory. I first purchased and installed 2 x 512MB 533 Mhz. It worked just fine with the old memory, just stepping down to 400 MHz - this was automatically done by system - I did nothing.
Later I replaced the original 256MB sticks with another 2 x 512MB 533 MHz. I then had 2 GB running at 533 MHz. All with no problem.
Before making the either purchase, I had read up and found several sourves that said mixing speeds by itself was not a problem.
 

thexder1

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Oct 18, 2006
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I ran mismatched memory in my system for years and never had any problems. I had 2 256MB PC2100 sticks of memory from Micron and 1 stick of DDR533 from ADATA. my computer even ran the 2 Micron sticks as dual channel at the same time it ran the single stick of ADATA as single channel, and there was nothing saying that the faster memory was being clocked down (although I don't see how it would work otherwise). This was all done on a Gigabyte board a while back, but I have done similar things on many different computers with different motherboards and CPU's. The only problem that can occur with this is if the memory that is being clocked down does not work at the slower speed (I ran into this problem when I first changed my computer to running 4 sticks of RAM due to it being clocked down to 333 instead of 400) or if for some reason the slower memory is being overclocked(not likely).
 

Mondoman

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rockyjohn is right. Just run memtest86+ through a few cycles with only the first pair installed, then run it with only the second pair installed. Any errors mean something's wrong. If both check out OK, install all 4 and run memtest86+ as a final check.
 

thexder1

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I don't know about Rockyjohn but when I was mixing different speeds of RAM I had run memtest86+, and docmem on my computer through several times each (let them each run over night) and never came up with any errors when doing it. The only time that I came up with errors was as I said in my previous post when I put int 4 sticks of RAM (which was when I bought 4 of the exact same type of RAM) which caused them to be clocked down to a speed that the RAM apparently did not like but changing the latency and frequency fixed that problem.