RAM Speed/Bus Speed Question

[jamiphar]

I currently have two PC2100 256MB sticks of RAM in my Compaq Evo and I was thinking of upgrading. With the Evo's P4-M having a 400mhz bus, would it benefit from having 400mhz (PC3200) RAM? Or is there something I'm missing here?

[Terrahawk]

It depends on whether the Northbridge's memory controller is able to run the RAM at 400 MHz. Many P4 chipsets from back in the days of 400 MHz bus P4s can't and are limited to 266 MHz or if you're lucky, 333 MHz support.

[jamiphar]

It depends on whether the Northbridge's memory controller is able to run the RAM at 400 MHz. Many P4 chipsets from back in the days of 400 MHz bus P4s can't and are limited to 266 MHz or if you're lucky, 333 MHz support.

I see. How would I be able to determine this? The laptop's motherboard is dead, but a good one is on its way here.

[Terrahawk]

Find out exactly what kind of chipset is on the motherboard. It's likely to be an Intel 845 of some sort. Once you know what sort of chipset it is, you can search for its specs on Google or download its datasheet from Intel's web site.

I had a Compaq Evo n1020V and it had an ATI RS200 northbridge with integrated video. That particular chipset only supported 266 MHz DDR RAM, as does the Intel 855PM in my Thinkpad R40 (a later revision of the 855PM does support 333 MHz DDR though).

[jamiphar]

Find out exactly what kind of chipset is on the motherboard. It's likely to be an Intel 845 of some sort. Once you know what sort of chipset it is, you can search for its specs on Google or download its datasheet from Intel's web site.

I had a Compaq Evo n1020V and it had an ATI RS200 northbridge with integrated video. That particular chipset only supported 266 MHz DDR RAM, as does the Intel 855PM in my Thinkpad R40 (a later revision of the 855PM does support 333 MHz DDR though).

This site shows it as an 845MP chipset, and Intel shows it as using 200/266mhz DDR RAM. So I guess that answers my question.

Another thing I just thought of, can the 845MP chipset support up to 2GB RAM, even when they're specified as supporting 1GB? I recall some of the T30s being able to use 2GB, are those 845MP?

[Terrahawk]

Have a search in the forums for the 2GB RAM on 845 topic. I have read quite a few posts that show that 2GB of RAM is possible, in R and A series Thinkpads.

[jamiphar]

Have a search in the forums for the 2GB RAM on 845 topic. I have read quite a few posts that show that 2GB of RAM is possible, in R and A series Thinkpads.

I searched and found this thread, which seems to suggest that the 845 chipsets can support up to 2GB.