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View Full Version : Downside of using too high spec ram?



WarNox
10-02-2010, 06:01 PM
Hey!

Since PC2100 is really old and expensive and PC3200 is backwards compatible (and cheaper) I am thinking of getting that instead. What would be the downside to this, if there is any at all? Its just for an old computer used for some backup tasks.

Thanks for any help.

Erayd
10-02-2010, 06:19 PM
There shouldn't be any downside - the fast stick should just downclock to match the other ram in the system (or if there's no other ram, it will match what the memory bus can handle).

Agent_24
10-02-2010, 06:56 PM
Yeah it should just run at the slower speed, no worries

(Does anyone know if this require the SPD to be programmed for these slower speeds for this to work?)

Speedy Gonzales
10-02-2010, 07:11 PM
Dont think so. I've never had to change the SPD. Its done it automatically

Agent_24
10-02-2010, 07:54 PM
When the RAM is made in the factory, SPD is written so the motherboard knows what timings to set at which frequencies (I'm sure you know that)

What I'm saying is, if you have DDR-400 RAM and the SPD is written for 2.5-3-3-7 @ 200Mhz for example, that's what it's going to run at by default.

Now say that it also has 2-3-3-6 written for 166Mhz. If you change clock in BIOS to 166Mhz (DDR-333) then it will change the timings by default.

What if SPD does not contain recommended values for the specific clock (eg: 166Mhz) you set it at? Or does this never happen?

Speedy Gonzales
10-02-2010, 09:03 PM
I have no idea. If I replace something and it works, I dont care lol

I removed the old CPU which is 800 fsb, (in this PC) and replaced it with a 1066 fsb CPU. A few weeks ago. It changed it in the BIOS from 200 to 266. This is using DDR2 800.

The only PC I had to fix up, (using DDR 400 ram), was when I was using a 533 fsb P4 CPU. I had to change the fsb in the BIOS to 266 (instead of 400, because the CPU wasnt 800 fsb), otherwise it wouldnt post / wouldnt boot into windows

pablo d
10-02-2010, 10:57 PM
What if SPD does not contain recommended values for the specific clock (eg: 166Mhz) you set it at? Or does this never happen?

If there's no SPD rating programmed for a selected speed - which rarely happens as mobos generally only give you the options to select common SPD speeds - then the mobo throws darts at a board and latency hilarity ensues. Generally it's on the same curve as the rest of the SPD value tho.