AMD K6 - runs at 475 MHz when chip says 500 MHz

[bruincal]

I have an older computer, an AMD K6 at 500 MHz. The chip itself has the etchings AMD K6 500 or some form of 500 to indicate that it is a 500 MHz chip. Yes, this is a pretty slow computer, but I'm just using it for email and web surfing. The thing is, software always reports the chip as being 475 MHz instead. I looked at the BIOS, and the settings in the BIOS say AMD K6, 100MHz FSB, clock multiplier 5x, and chip running at 500 MHz. However, when I run software like WCPU, it reports:

Processor #1 : AMD K6-2 (Model 8) / 3AD1EF99
Platform : Socket 7 (PGA Socket)
Vendor String : AuthenticAMD
CPU Type : Original OEM Processor (0)
Family : 5 (6)
Model : 8 (8)
Stepping ID : 12 (12)
Brand : ----
APIC : ----
HT Log.CPU Cnt : ----
Name String : AMD-K6(tm) 3D processor

Internal Clock : 475.28 MHz
System Bus : 95.06 MHz
System Clock : 95.06 MHz
Multiplier : 5.0

L1 I-Cache : 32K Byte
L1 D-Cache : 32K Byte
L1 T-Cache : ----
L1 Cache : ----
L2 Cache : ----
L2 Speed : ----

MMX Unit : Supported
SSE Unit : Not Supported
SSE2 Unit : Not Supported
MMX2 Unit : Not Supported
3DNow! Unit : Supported
3DNow!+ Unit : Not Supported

Host Bridge : 1039:0530.03 [SiS 530]
IDE Controller : 1039:5513.D0 [SiS 5513]
VGA Device : 1039:6306.A3 [SiS 620/530]
Memory Size : 152M Byte
Memory Clock : ----


I am running on a PCChips 598LMR socket 7 motherboard (yeah its a pretty ghetto motherboard).
I know that this problem is very trivial (+- 25MHz, no big deal), but I'm just wondering ...
I am thinking that maybe the chip was fradulently marketed as a 500 MHz with fake etchings??
I bought the system from an online vendor that is no longer in business...

Thanks!!

 

[Lord Evermore]

Notice that your bus speed is reported by the software as 95.06MHz. 5 times 4.94 is 24.7, the same amount that your CPU speed is off from optimal.

Many motherboards slightly underclock the various bus speeds from "perfect" clock speeds, some slightly overclock it. In this case, I think your speed is vastly underclocked (usually we're talking about 0.2MHz difference).

I found a couple of specification lists of that board, and they mentioned supporting a 95MHz bus. K6-2/333MHz used a 95MHz bus with a 3.5X multiplier.

This site also has a mention of the 100MHz setting producing a 95MHz bus on this board. The BIOS they list (which the link isn't good for) apparently fixes that.

 

[SemperFi]

As I recall k6 boards had jumpers or switch blocks to adjust the settings. I had several k-6's and one of them used a bus of 95 Mhz I think it was the 333Mhz one. It has been a while though.

 

[Zepper]

Some BIOS don't read actual clock speed, just reflect the settings. Software often actually measures the clock. Looks like you're actually running 95MHz FSB. Look for the BIOS update as suggested above if you're panties are really in a bunch about it.
.bh.

 

[TheCorm]

I believe there was a K6-2 475mhz CPU so like others have said, the settings are probably set to that, Bios update and then you should be able to adjust. Super-7 boards generally had jumpers so check these too.

 

[coolVariable]

You probably just have to adjust the jumper settings on that board to 100MHz FSB!

 

[jonmullen]

Originally posted by: bruincal
II know that this problem is very trivial (+- 25MHz, no big deal), but I'm just wondering ...
I am thinking that maybe the chip was fradulently marketed as a 500 MHz with fake etchings??

Tell that to the hardcore overclockers. They will do crazy stuff for 25mhz But so would I.