JmE

Thanks to posts by Planet-II and others, I checked my PXA255 Axim Advanced (running PocketPC 2002) and apparently the default state for the processor settings are for a 100 MHZ (99) internal bus (PXBus). It should be 200 MHZ (199) since it is a PXA255 and the information on the Intel site does not lead me to belive that hardware changes made by Dell are likely a cause.

It was first brought up in relation to CPUID v1.3 showing a PXBus speed of 200 (199) on the HP 2215 and 100 (99) on a PXA255 Axim Advanced. After disabling Pocket HackMaster, my Axim confirmed these findings. I also checked with Pocket HackMaster's fetch function and it appears that the Axim sets the system to L=27 M=2 N=2 which would result in an internal bus speed (PXBus) of 100 instead of what it should be, 200.

After using Pocket HackMaster to set the values to L=27 M=4 N=1, CPUID reports my Axim as running a PXBus of 200. Indeed, the results from CPUID for the 2215 and Axim are identical. This leads me to believe that it is not a hardware limitation of the Axim but maybe a firmware problem in which Dell has the Axim booting with a PXBus of 100 and not switching the PXA255 processors over to the normal PXBus speed of 200.

Perhaps this is linked to the "firmware bug" that Dell is currently wrestling with? Why is the axim running the PXBus at 100 by default when it can clearly use the PXBus at 200? (according to the Intel documentation, a motherboard redesign is not necessary to run the PXA255 at an internal bus speed of 200... which is demonstrated by being able to run the Axim with a PXBus of 200). Is CPUID wrong or what's up?

Any thoughts or comments would really be appreciated.

-JmE-

chog

Is this on the new MM2003 or on PPC 2002?

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JmE

On PPC 2002... but if the information I am seeing is correct, it could be in the firmware and carried over to 2003. It would mean that the stock PXA255 Axims out there are running the internal bus at half the speed they should be! I think this is a real important thing if correct.

It appears to me that Dell has it set up to run with the wrong setting (L=27 M=2 N=2) instead of the Intel correct setting of (L=27 M=4 N=1).

What do you think?

Right now I have my Axim running at 400 MHZ (398) with the internal bus where it should be, 200 MHZ (199) and it is running smoother than it ever has with PPC2002.


-JmE-

PDANewbie

But if that were the case what would cause the 03 to run a lot slower than the 02? If both were using the same settings...

chog

Are you using 2002 or 2003 JmE??

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JmE

I am just speculating there, but 2003 is designed to utilize the Xscale more fully, right? What if you cut the internal bus speed of that Xscale in half? Lousy performance!

The PXA250 processor has an internal bus speed of 100 anyway and people were saying they did not see much of a difference between PXA255 PPC 2002 and PXA250 PPC2002. Well, if this default Axim setting is correct, then they would not see much of a difference!

My point is that those of us running Axims with a PXA255 stock might be running it at half the internal bus speed for no good reason.

-JmE-

JmE

Quote:

Originally posted by chog Are you using 2002 or 2003 JmE??

2002

-JmE-

JmE

Here is how anyone can check...

Go to http://www.pocketpccity.com/software...-pocketpc.html and download CPUID.

Copy it to your Axim.

Make sure all overclocking software is turned off.

Run CPUID and check the PXBus line in the results. Please let me know what speed it has there and what the L, M, N values are returned (L will probably be 1, I think a difference in CPUID and the rest of the world).

If you have a PXA255 and the Axim is setting itself correctly, the PXBus should be 199 MHZ if not, it will be 99 MHZ.

Please post here when you try it.

Thanks,

-JmE-

JmE

CPUID apparently also runs in 2003 as Planet-II had posted some screen shots from an HP 2215.

I am curious if someone with 2003 could run CPUID and post the PXBus result and the L, M, N values here.

Please?

-JmE-

chog

Mine says 99mhz bus frequency and L-1 M=2 and N=4

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steelvulture

I have 2003. CPUID says the same thing as chog.

JmE

Yep, that is what my stock Axim had. I used Pocket Hackmaster to set it where it should be per Intel (by way of cageyjames ;) ) of m=4, n=1 and CPUID produces results identical to the HP 2215. I am ignoring the L beacuase I think CPUID is using a different scale or something (L=27 is default and normal with Pocket Hackmaster).

When I set mine to m=4, L=1 PPC2002 became really smooth.

Steelvulture, do you want to set yours at (L=27) M=4, N=1 and post about how PPC2003 runs and what CPUID shows?

-JmE-

JmE

In this thread http://www.aximsite.com/boards/showt...1&goto=newpost about half way down on the first page (I think) you can see the screenshot of CPUID on an HP 2215 with a stock PXBUS of 199 MHZ.

Please don't post replies to this thread there as we had gotten a little off topic in the other thread and I don't want to create duplicate threads.

-JmE-

Astounded EEG

L=1 M=2 N=4

dan12

My Axim basic (WM2003)(PXA255 of course) says L=1, M=2, N=3. I don't know if I want to try overclocking, but I would if that's not how it is supposed to be, hope Dell remembers to look at that while working on their fix.