Bus Speed of 478 CPUs in relation to Rambus/RDRAM

[Guest]

I have a box that can't really be replaced with a new machine right
now, but really could use just a boost in CPU speed. Generally I would
just buy a new box, or MB/CPU combo, but in this case I'm realizing
just dropping a new CPU may be better in the short term.

Basically, its a Intel Mobo with the i850 chipset, and a single 512mb
RDRAM 800mhz. The CPU in it a Socket 478 P4 2000mhz with 400mhz bus.

I'm not as familer with RDRAM , I remeber discussion on awhile back,
but can't remeber the technical things about how its bus speed was
running. I think the rambus 800mhz was really just 400 doubled. Does
this mean I can not run a Socket 478 CPU that wants a bus speed of
533mhz?

[Bob Knowlden]

If memory serves, if you want official support for a P4 with a 533 MHz FSB,
you'd need an 850E chipset rather than the original 850. (You'd also want
PC1066 RDRAM, if you wished to run it at 1:1 off the bus. That would give
best performance, but it's probably not required.)

It may be possible to run the system out-of-spec with a 533 MHz CPU. I
suggest searching Google Groups, or just plain Google, under the model name
of the mainboard.

HTH.

Address may be scrambled. Replace nkbob with bobkn.

<matobinder@idcomm.com> wrote in message
news:1104955658.581787.288260@z14g2000cwz.googlegroups.com...I have a box that can't really be replaced with a new machine right now, but really could use just a boost in CPU speed. Generally I would just buy a new box, or MB/CPU combo, but in this case I'm realizing just dropping a new CPU may be better in the short term. Basically, its a Intel Mobo with the i850 chipset, and a single 512mb RDRAM 800mhz. The CPU in it a Socket 478 P4 2000mhz with 400mhz bus. I'm not as familer with RDRAM , I remeber discussion on awhile back, but can't remeber the technical things about how its bus speed was running. I think the rambus 800mhz was really just 400 doubled. Does this mean I can not run a Socket 478 CPU that wants a bus speed of 533mhz?

[Tony Hill]

On 5 Jan 2005 12:07:38 -0800, "matobinder@idcomm.com"
<matobinder@idcomm.com> wrote:
I have a box that can't really be replaced with a new machine rightnow, but really could use just a boost in CPU speed. Generally I wouldjust buy a new box, or MB/CPU combo, but in this case I'm realizingjust dropping a new CPU may be better in the short term.Basically, its a Intel Mobo with the i850 chipset, and a single 512mbRDRAM 800mhz. The CPU in it a Socket 478 P4 2000mhz with 400mhz bus.

That probably means that you are SOL.
I'm not as familer with RDRAM , I remeber discussion on awhile back,but can't remeber the technical things about how its bus speed wasrunning. I think the rambus 800mhz was really just 400 doubled.

That is true, though it has little to no relation to the processor's
bus speed. Two separate buses you're talking about here.
Doesthis mean I can not run a Socket 478 CPU that wants a bus speed of533mhz?

In and of itself, no. However the fact that the motherboard uses an
i850 chipset most likely will prevent you from using a 533MT/s bus
speed P4. The actual i850 chipset did not support anything faster
than 400MT/s bus speeds, though the i850E chipset added support for
533MT/s bus speed chips. However, the i850E chipset was also VERY
rare and almost always only included alongside CPUs that were actually
using said 533MT/s bus speed. You might want to check your
documentation for the system to see if it does indeed use the i850E
chipset instead of the original i850, but chances are that you're
limited to 400MT/s bus speed processors.

Now, you do still have some upgrade options available. Intel did make
P4 chips with a 400MT/s bus speed at up to 2.8GHz, and all of them
*should* work on your board (check the documentation to be sure
though). I just checked www.newegg.com and they list the 2.8GHz P4
with 400MT/s bus speed at only $169, which is actually a lot cheaper
(and easier to find) than I was expecting.

-------------
Tony Hill
hilla <underscore> 20 <at> yahoo <dot> ca