VisorCentral.com - Overclocking experiences

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VisorCentral.com (http://discussion.visorcentral.com/vcforum/index.php)
- Visor & Deluxe (http://discussion.visorcentral.com/vcforum/forumdisplay.php?forumid=1)
-- Overclocking experiences (http://discussion.visorcentral.com/vcforum/showthread.php?threadid=8842)

Posted by FrostyBurn on 10-21-2000 06:55 PM:

I was considering overclocking my visor deluxe, as in the default clock speed. I was going to try 20mhz first, but I wanted to know everyone elses experiences with it. I know it affects battery life, but will it damage the processor? please comment.

Posted by BEN on 10-21-2000 08:06 PM:

I have mine overclocked to the fastest degree for many of my programs, and it works fine.
BEN
PS using Afterburner 2.2

Posted by VoxDei on 10-21-2000 09:39 PM:

I don't know what it is...I've tried AfterBurner many, many times over the past ten months, and I've never had a satisfactory experience. I've got the latest version and I still got crashes on a regular basis. I tried setting only my "slowest" programs to fast speeds, and still had problems. In addition, it cuts my battery life in half. I have no idea what other folks have no problems, and I've had so many, but that's my experience!

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Posted by FrostyBurn on 10-21-2000 09:40 PM:

I want to know if anyone has their DEFAULT speed overclocked.. and leaves it like that; I need to know if this will burn out the processor, because im considering it.

Posted by tyler on 10-22-2000 12:04 AM:

I've had the default speed (using AfterBurner) set at 28 MHz for about nine or ten months now. Of late, I have seen some issues with some hacks crashing too often, so I backed it down to 24MHz. I'm not sure yet if this is the remedy. (I also want to be WOW-ed by the 33MHz Prism when it arrives, so this seemed like a good excuse to slow things down. ) I would definately recommend it, but you may need to back down a little if things get unstable. (The difference in 28MHz and 16MHz is VERY aparent.)

tyler

Posted by FrostyBurn on 10-22-2000 12:20 AM:

okay, so I am guessing that if i set the default clock speed to 20mhz it should be fine..

Posted by kalahari on 10-22-2000 02:18 AM:

I had my Visor Deluxe set at 26MHz for many months without issues. I don't think I need to overclock my Prism although I might try QuickBits on it.

Posted by JJinNJ on 10-23-2000 06:15 AM:

Faster = Hotter = Fails Sooner

Overclocking any processor means it will run hotter.
When any electronic device runs hotter, it will fail earlier than it would have without over-clocking.

Posted by MPM on 10-23-2000 09:33 PM:

Reality check...

quote:
Originally posted by JJinNJ
Overclocking any processor means it will run hotter.
When any electronic device runs hotter, it will fail earlier than it would have without over-clocking.

Ok, time for an engineering reality check...

While the statement "faster = hotter = fails sooner" is true, the Visor's CPU, the Motorola Dragonball EZ, consumes very little power. It can't consume gobs of power and still give you 1-2 months of battery life.

So let's run the numbers and see just how much hotter the CPU will run when overclocking a Visor Deluxe to 28MHz.

According to the Motorola Dragonball EZ datasheet the maximum current the CPU will draw running at 16MHz is 20mA. The CPU runs at 3.3V. So that gives us 66mW of power (heat) dissapation.

Now with CMOS type ICs (like the Dragonball), doubling the clock rate, doubles the current consumption. So increasing the CPU to 28MHz by overclocking will increase the current consumption by a factor of 1.75 (1.75=28/16). So now at 28MHz the maximum CPU current consumption will be 35mA and the power dissapation will be 115.5mW.

The temperature rise of the CPU can be computed by using the junction to ambient thermal resistance of the CPU package. Unfortuneatly, Motorola does not specify this in the datasheet. The package they use (a 100 pin TQFP) is a standard one, so I used another manufactures number. They had the thermal resistance of the 100 pin TQFP package at 31 deg C per Watt. This means the for every Watt of power dissapated by the package that the junction temperature of the chip inside the package will increase by 31 deg C.

So for our tiny increase of 49.5mW (115.5mW-66mW) the Dragonball CPU temperature will increase by just 1.5 degrees C! That's just 2.7 degrees F!

Now let's say that Motorola's package is not 31 deg C per W. Say is is double that (very unlikely). Then the worst case temperature rise is just 3 degrees C! (5.4 degrees F)

Now the above analysis does not take into account the the CPU is hooked up to other components and is not running alone. This will add a bit to the power draw because the Dragonball will have to drive the signal lines connecting it to the other components (RAM, ROM, etc...) So let's just double power dissapation (again somewhat too much). This simply doubles the temperature rise. So now we have a 6 deg C increase.

Believe me, even a 6 deg C temperature rise will NOT effect the life of the CPU. (If it did effect it that much, electronic products in the hotter regions of the world would be failing at a much faster rate then ones in the cooler regions.)

So in the worst, worst case scenario, we have a 6 deg C (11 deg F) temperature rise when overclocking to 28MHz. i.e. Don't worry about it! Overclock!

P.S. I'm going to overclock my Visor to 24MHz (default) at my next battery change, and see what effect it has on my battery life. I'll post some results when that set of batteries dies.

P.P.S. I'm going to use 24MHz instead of 26MHz or 28MHz because at 24MHz the serial port and IR beaming will work. They don't work properly at 26MHz or 28MHz.

Posted by puppy1chow on 10-23-2000 11:09 PM:

Has anyone overclocked their Visor Prism yet, and is it possible? Thanks.

Posted by FrostyBurn on 10-23-2000 11:09 PM:

WOW! thanks A LOT, wait... A LOT!
Thanks for working out the math, and showing us that overclocking our visors, really WONT damage it, WHATSOEVER. I appreciate the time you took to write such a detailed response, and I think this will convince me to overclock my visor. no need for the platinum now, 24mhz suits me fine!

Posted by jj_w on 10-24-2000 01:33 AM:

I am very interested in overclocking my Platinum. Anyone who has tried this, please post your experience.

Posted by perze_a on 10-24-2000 09:37 PM:

I've been overclocking my BVD at 24MHz for over 5 mos. now, no problems encountered so far. I'm always ticked off when after a certain time, it reverts back to its standard 16MHz... is this normal? is there something that I can do to make it stay at 24MHz? I'm using After burner V2.0

Perze

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Posted by lennonhead on 10-27-2000 10:01 PM:

My battery seemed to drain faster while running at 28 MHz. Fine for the occasional app that needs it, but I don't keep it set as the default.

Posted by imabug on 05-23-2001 08:38 PM:

Overclocking benchmarks

Having used Afterburner 3.0t and 3.0u on my Platinum for a while, I thought I'd try Quickbits on top of it. With afterburner alone clocking up things like Quicksheet and ThinkDB to 45 MHz, I noticed a fairly nice improvement in performance. With the addition of Quickbits, there appears to be some incremental performance. Accessing tables in ThinkDB seemes to be a little quicker.

So, I thought I would post some benchmarks as reported by PocketMark and Quickbits. Benchmark did not appear to test any of the Quickbits optimizations.

AB = Afterburner 3.0u (includes other optimizations on)
QB = Quickbits 1.1

PocketMark (numbers represent PocketMark PALMMARKS)
Platinum - 198
Platinum + QB - 262
Platinum + AB (45 MHz) - 306
Platinum + AB + QB - 361

Quickbits benchmark (numbers represents QB Index)
Platinum - 144
Platinum + QB - 487
Platinum + AB (45 MHz) - 198
Platinum + AB + QB - 665

It's interesting to note that PocketMark and Quickbits report the opposite when running afterburner or quickbits alone.

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Posted by Desimike on 05-25-2001 06:15 AM:

Afterburner?

Afterburner 2.0 vs 2.2? Which is better? Is it just used for overclocking? Where do you get it? (I just purchased my first VDLX and am trying to get into the "know" Plz help

Thanks

Posted by imabug on 05-25-2001 01:40 PM:

Re: Afterburner?

quote:
Originally posted by Desimike
Afterburner 2.0 vs 2.2? Which is better? Is it just used for overclocking? Where do you get it? (I just purchased my first VDLX and am trying to get into the "know" Plz help

Thanks

The latest version is 3.0u, so I would think that one would be better. Find it at PalmGear.

Afterburner does a few things. Overclocks the CPU (up to 45 MHz for the purchased version), eliminates wait states, does some optimization to memory access and some screen stuff.

Posted by Desimike on 05-25-2001 01:49 PM:

Thanks for the info imabug I'll pick it up right away.

Posted by slawyer on 06-08-2001 02:23 AM:

VDX and Afterburner 3.0u - Anyone getting faster than 24MHz?

Just installed Afterburner for the first time today (registered) version 3.0u and get nothing but errors when trying to run it at 24MHz or above. Works fine at 23MHz. Followed recomendations that came with it, but get fatal errors and hangs. Any advice would be appreciated.

Scott

Posted by enhanceyourlife on 06-08-2001 02:37 AM:

Best I can do with my Plat is 41MHz. Any higher than that and it chokes. I haven't tried it on my VDx yet.

One thing I use that helps with the hacks, is TealMaster. It allows the setting of the priority of the various hacks installed.

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