Can I use SDRAM and DDR together?

[a2ross]

Upgrading a system. The new mboard has slots for both SDRAM and DDR RAM. I am buying some more RAM with the upgrade but still want to use the SDRAM I have. Can I use DDR with the SDR. I so far gather that if it is possible, all the RAM will only run at the slower speed. This I can handle. I just need to confirm that I can run both together.

Thanks in anticipation.

 

[Pyramus]

Are you sure the motherboard has slots for both types of RAM? That sounds weird to me.

 

[a2ross]

Yes, I'm sure. Below is the link to the manufacturer's site for this particular board.

http://www.asus.com.tw/mb/socketa/a7a266-e/overview.htm

I can find lots of comments around about the merits of various different types of RAM and which would be better for what type of system but can't find a specific reference to using both on the same board.

Please help.

 

[MichelleButler]

There are boards available for DDR and SDRAM, but you will find that you will have to disable one type of memory in the bios to get the other type of memory to work. They will not work together. I have such a motherboard, and you have to disable the other type.

I hope this helps.

Michelle

 

[a2ross]

Thanks Michelle.

I've since found the downloadable manual for the motherboard in question and it specifies that the two type of RAM are not to be mixed.

Thanks for the help.

Arthur

 

[ceh4702]

If you could use two types of ram you would have to run bus that the RAM is on at the speed of the slowest RAM. I would buy the RAM now. You can probably get a discount right now. I dont think DDR can run at the SDRAM speed. Either that or the voltage is different.

I think the motherboard you want to use will have problems. Better check it out a little more. If you do not like my post feel free to point out your opinion or my errors.

 

[cdogg]

You've already got your answer, but if you think about it, you wouldn't want to even if you could.

For example:
You're performance would likely be better off with the 256MB of PC2100 DDR RAM by itself running at 266MHz (133MHz x 2 "dual-pumped&quot rather than 512MB total RAM running at 133MHz.

Plus, no point in spending the extra money on DDR if you're going to cripple its speed...


~cdogg

 

[jpm121]

cdogg,

I'd rather have 512 MB than 256 any day, any speed, any anything. The benchmarks I've seen show that the memory speed has an incremental effect on overall performance while getting to 512 MB can be a major plus. It's not like your computer runs twice as fast from 133 to 266.

Just my opinion...

 

[cdogg]

jpm121,

Good point. In some situations, having 512MB of RAM is more important that having 256 running at a faster speed (like if you were running WinXP whose sweet spot according to many reviews is 512MB).

I also understand that DDR doesn't produce twice the performance. In many benchmarks, only about a 5-15 % increase is noticed depending on the apps/games you run.

However, in other OS's like Win95/98, 256MB would probably be the better option (due to a serious flaw in the Win9x kernel). Since a2ross never said what OS he had and almost 50% of the desktops out there are Win98, that's why I said 256 DDR is likely to benefit you more.

 

[a2ross]

Thanks for all the input.

I'll be getting the 256MB of SDR. I agree that 512MB of anything is better than 256MB of DDR.

The idea was to try to avoid throwing away RAM if possible. If the DDR would have run with the SDR (even at the same performance as SDR) I would have effectively 448MB of SDR. Then when I wanted to go full DDR, I'd only have to buy 256MB of it and remove the current 192MB of SDR.

It now means that I buy the 256MB SDR and use it until I can afford to buy a full 512MB DDR and then just get rid of all the SDR.

If that doesn't make sense, I'm not really surprised as it even confuses me when I read it but I haven't got time to make it clearer at the moment.

Arthur

PS Running Windows2000 Pro so larger amounts of RAM is not a problem.

 

[jpm121]

Good call cdogg, and I couldn't agree more re: too much memory in Win98. Really gives you a great deal of faith in the Redmond geniuses doesn't it??

 

[cdogg]

hehe...