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View Full Version : Battling brothers - XScale or StrongARM Processor?

Jason Dunn
11-07-2002, 08:10 PM
<a href="http://www.tomshardware.com/mobile/02q4/021107/index.html">http://www.tomshardware.com/mobile/02q4/021107/index.html</a><br /><br />Tom's Hardware has published an article on some of the issues with StrongARM CPUs vs. Xscale, but the author doesn't go into much detail on the real crux of the issue. The battery life tests are interesting - I still don't have an Xscale device to do battery tests on. It's interesting to see how poorly the Loox fares in some of these tests.<br /><br />"In the market for a new PDA, but don't know which one to buy? The choice just got murkier. Should you get an expensive model with the latest Intel XScale processor, or can you get by with a cheaper version based on its older brother, the Intel StrongARM processor? The new Intel XScale PXA-250 CPU is already cranking away at 400 MHz in the Asus MyPal A600 and the Fujitsu-Siemens (FSC) Pocket Loox. Yakumo's Alpha, has to make do with the widely used StrongARM processor SA-1110 and 206 MHz."
Yuta
11-07-2002, 08:55 PM
If Xscale is faster, then how comes software runs slower??? :?
ECOslin
11-07-2002, 09:15 PM
Yessss, more mips, less power used.

I like the fact that theoretically using an Xscale processor I could get 800 Mips for 1 Watt, instead of, with an StrongArm, 233 Mips for the same cost.

Is there a problem with Xscale? is it slow?

Edward
Jonathon Watkins
11-07-2002, 09:43 PM
From THG:

Users have grown accustomed to one of the XScale's quirks: while the 400 MHz clock speed of XScale PXA-250 processors is twice that of the SA-1110, you won't notice any difference in speed when running your programs. On the contrary, some applications are even a touch slower. The only programs that get any boost from XScale's architecture are those that work directly with the CPU.

Ummm - guys - how have you missed this? This has been BIG topic ever since the XScale processors were intoroduced months ago. :?
sponge
11-07-2002, 10:00 PM
They really didn't miss anything, this is one of their first (if not first) articles about PDAs, specifically PocketPCs.
Jonathon Watkins
11-07-2002, 10:07 PM
They really didn't miss anything, this is one of their first (if not first) articles about PDAs, specifically PocketPCs.

On THG perhaps - but it's been all over this (and every other) PPC site for months.
roberto_torres
11-07-2002, 10:59 PM
We must put pressure into Microsoft to add support for Xscale.


Even Palm OS is optimized for the XScale, why does not MS optimizes PPC already???

:microwave:
heov
11-07-2002, 11:09 PM
who said palm os is optimized for Xscale? I don't think it is, it runs on ARM 7 I think; Xscale is ARM 10; anyway, even if it was, it's probably because they didn't have to go through StrongARMS, they jumped straight to Xscale...
Kirkaiya
11-08-2002, 12:13 AM
who said palm os is optimized for Xscale? I don't think it is, it runs on ARM 7 I think; Xscale is ARM 10; anyway, even if it was, it's probably because they didn't have to go through StrongARMS, they jumped straight to Xscale...

I don't think that Palm OS5 is optimized for XScale - I haven't seen that claimed anywhere by Palm, in any case, and their own ARM-based device, the Tungsten, uses TI's OMAP chip, which has an ARM core (and I'm pretty sure that Texas Instruments hasn't ripped of the XScale mods for the OMAP).

I think the crux of the problem is that Intel has added enhancements to the ARM core, and changed the architecture - while it's backward (sideways?) compatible with the StrongARM and other ARM processors, unless software is specifically written to use those enhancements, then that software isn't going to see a big speed boost.

On the other hand, there have been video-clips of an iPaq pre-XScale (StrongARM SA1110) side-by-side with an XScale-based unit (a Toshiba, I believe) that *DID* show some signficiant speed boosts with the XScale for certain applications (I believe it was a game called Lemon, or something), while it was just slightly slower when opening a big Acrobat PDF file.

I'm starting to think that Intel is to blame here, in a way. It's a bit like the Intel MMX graphic extensions versus the AMD ones (3d Now, or something?) back when the Pentium II and AMD K-6/7 were out. They were competing graphics extensions, and game developers felt the pressure to support both.

With the ARM core, however there is Intel, Motorola, Samsung, and probably more licencees of the technology (and who would have believed a UK chip design would gain such dominance!!).

Is Microsoft obligated to support the propietary extensions of ALL of them? I think that would lead to either a fatter OS, or compatibility problems (remember all the damn issues when we had SH4, MIPS, and ARM ??).

Soo... I think XScale is a great technical achievement, but unless/until they are the defacto PocketPC processor, I don't blame MSFT for waiting.
Rirath
11-08-2002, 01:36 AM
Ignoring the whole waste of breath that is the Xscale vs Arm debate on these forums, I was particularly annoyed by the article. The devices he used were of little to no interest to me, and the benchmarks were too abstract.
Duncan
11-08-2002, 02:45 AM
Ah well... if the devices he used were of little interest to YOU he clearly shouldn't have bothered, I mean what was he thinking?? :roll:
Take1
11-08-2002, 08:53 AM
http://www.tomshardware.com/mobile/02q4/021107/images/image006.gif

The battery run time on the ASUS was impressive.

The Loox did horrendously poor on battery life.
Jonathon Watkins
11-08-2002, 11:19 AM
I used to read THG back in 95-96 when it was actaully worth reading. It's gone seriously downhill since then. I would take most of THG with a big pinch of salt these days.

the benchmarks were too abstract.

Fair point.
Yuta
11-08-2002, 06:52 PM
From THG:

Users have grown accustomed to one of the XScale's quirks: while the 400 MHz clock speed of XScale PXA-250 processors is twice that of the SA-1110, you won't notice any difference in speed when running your programs. On the contrary, some applications are even a touch slower. The only programs that get any boost from XScale's architecture are those that work directly with the CPU.

Ummm - guys - how have you missed this? This has been BIG topic ever since the XScale processors were intoroduced months ago. :?

I'm completely aware of this issue. SA-1110 has ARM V4 intruction set and Xscale has ARM V5 set. (And not V8 or V10 as stated before) ARM V5 set is able to run ARM V4 code. Pocket PC's OS is made on ARM V4 set.

Now, if the chip can make more integer and float calculations it is actually faster. The fact that Microsoft doesn't optimize the OS for the V5 set and its poor extensions has nothing to do here. The faster the code goes, the better.

I'm tired of hearing that the OS is not optimized for Xscale, but noone seems to explain why (taking into account the fact that it can excecute code faster).
Just because memory r/w operation is kinda slower?. Maybe, but I'm sure someone with more solid knowledge of the software can give a better explanation.