Can a CPU's FSB rating exceed the MOBO's FSB rating and still operate?

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blargg27

Can a CPU's FSB rating exceed the MOBO's FSB rating and still operate?
(NOTE: I expect it to run a 266mhz, I'm not looking for 333mhz.)
I only ask due to lack of retail 266mhz cpus available.

For example, I have the following setup:

ECS Elitegroup L7VMM2 Motherboard
Specs: http://www.ecsusa.com/products/l7vmm2.html

It has VT8375 Northbridge and VT8235 Southbridge chipsets. It tops out
a 266 FSB.

I want to purchase this CPU: (it has 333mhz FSB)
http://www.newegg.com/Product/Product.asp?item=N82E16819103377


Here is a list of officially supported CPUs from AMD:
http://www2.amd.com/us-en/recmobo/DetailHandler/1,,30_182_869_4348^7923,00.html?queryID=2111

The CPU in question is of course, not on the list.

Remember, I do not wish to run the CPU at 333mhz. I only care if the
computer will run.

Thank you in advance!!

-Ben Ford
 
Can a CPU's FSB rating exceed the MOBO's FSB rating and still operate?
(NOTE: I expect it to run a 266mhz, I'm not looking for 333mhz.)
I only ask due to lack of retail 266mhz cpus available.

For example, I have the following setup:

ECS Elitegroup L7VMM2 Motherboard
Specs: http://www.ecsusa.com/products/l7vmm2.html

It has VT8375 Northbridge and VT8235 Southbridge chipsets. It tops out
a 266 FSB.
Click to expand...

Among the most likely problems is that ECS boards have
quirky bios that can do odd things when another CPU is
installed. You may need to clear the CMOS for example, or
it might halt unnecessarily when it can't ID the CPU. The
former is more likely than the latter. I don't mean to
suggest it won't work, rather that it probably will but
being an ECS board there is a slight chance of related
complications.

I want to purchase this CPU: (it has 333mhz FSB)
http://www.newegg.com/Product/Product.asp?item=N82E16819103377
Click to expand...


2.083GHz as 12.5X multiplier, 166MHz clock rate FSB, NOT
333MHz FSB. It would be DDR333 FSB though. Yes I know
that's how Newegg lists it, and that is technically wrong.

Anyway, because your board only supports DDR266 FSB and the
multiplier is locked, it would only run at 1.67GHz, as 12.5
X 133.33MHz.

Further, the other big issue is that it's a Barton. That
alone makes it far less likely to work. It is possible,
other makes of KT266 & KM266 boards have been able to run
Bartons, but I wouldn't bet on it with ECS... you'd have to
try it and see.

The safer bet would be to try a plain old Athlon XP2100,
which starts with the correct FSB, still uses 12.5X
multiplier, and will end up running at 1.67GHz. It'd be a
little slower than the Barton, but then Bartons are what may
not work. It can be hit-or-miss getting them to run on any
given board, someone will have a couple old socket A boards
and be able to get a Barton to run then conclude that "all"
skt A boards will run them but it's not so clear-cut.
Unfortunately no manufacturer is going to list them as
supported since they don't have a compatible FSB speed even
if they would POST and run ok.
Here is a list of officially supported CPUs from AMD:
http://www2.amd.com/us-en/recmobo/DetailHandler/1,,30_182_869_4348^7923,00.html?queryID=2111

The CPU in question is of course, not on the list.

Remember, I do not wish to run the CPU at 333mhz. I only care if the
computer will run.
Click to expand...


IMO, you should just follow the list and get the XP2400 on
it. If you had the Barton already it shouldn't hurt to try
it but to buy one for it doesn't seem worth the odds of it
not working. You might Google search for owners of the
board to see if anyone has tried a Barton (any Barton except
a mobile, since the mobiles have a different default
multiplier and FSB).

Frankly you're better off replacing more than just the CPU
if you're looking at spending $135 for an Athlon XP2800
alone. KM266 wasn't necessarily a bad motherboard chipset
for it's time, but the integrated video along with limited
FSB means it's going to bottleneck performance more the fast
a CPU you had installed. Plus, such boards weren't targeted
for the higher amperage of more modern CPUs, there is a fair
chance the board's lifespan will be reduced.
 
Thank you very much for the detailed reply. I couldn't find any data
specifically stating a stance in either direction, hence my posting to
this group.

This is my job's equipment, and it was purchased by someone else...I
will probably limp them along and replace them with better boards in
the future anyway. I dislike ECS boards as it is...

After posting I did notice that newegg has wrong specs on a few
processors, so this reinforces my constant research elsewhere before
even considering a purchase.

Lastly, my motivation for this question was more out of curiousity then
saving money.

Anyway, I thank you for the reply. Greatly appreciated!
 
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