I confirmed the speeds with Conky and don't understand why the phone feels a little more responsive with the 600mhz kernel than 800mhz...


I got the 800mhz from here

http://theunlockr.com/2010/04/05/how...ur-nokia-n900/


And the 600mhz from here

http://maemocentral.com/2010/04/04/h...he-nokia-n900/

how long had you been using the 800mhz for? the increase in speed may just be due to the reflash, i did a full reflash on mine after oc'ing at 900mhz and was suprised that it was quicker than it had been before oc'ing, but the best part was that it got quicker still after installing titans maemo25 kernel i can now change between stock and all the other different clock settings at will using Qb widgets and can see the increase in performance at every step.
So i think your improvement in performance is down to it being freshly flashed,
I would def recomend titans maemo25 as it reverts to stock after every boot up so you'll be able to notice any difference.
I have Qb widgets set up for ideal, xlv, stock, one to limit cpu to 500mhz at night and one to set max freq to 1ghz, i also use cpufrequi to set smart reflex and ignore nice load and less often used freq's.

One thing you may be seeing is a side-effect of how flash works. Flash emultating a disk can be quite lossy depending on how it's done. Most flash devices have an internal bitset that tells them which cells contain data and which don't. If you write to a cell that doesn't have data, it just does a write. If you write to one that's marks as having data (even if that data is no long important, from a deleted file, etc), if you're not writing out the whole block the flash manager does a read, merge, write, which takes more time.

That shouldn't affect swap performance (assuming the swap block size matches the flash block size, and the partition is "formatted" to align properly). But even something like writing files to flash is much faster on a clean device vs one that's had data on it and had it deleted.

A nice little app would be one that finds the "empty space" on your flash memory and resets those bits in the flash controller. But that's usually something you need a special API to do from the chipset manufacturer. (Intel Gen2 solid state drives, for example, have such an interface.)

Any flash design has no meaning here - h3llraz0r flashed KERNEL. That means - it is read once during boot and never touched after boot. So, flash peculiarities have no value in acceleration.

But it has sense to compare with PREVIOUS 600MHz - it is possible that 800MHz kernel actually runs on very different frequency. There are reports that 800MHz is not the best frequency for N900 CPU and because of that it may run on different frequency but not 800MHz.

Or - alternatively - it is possible that 800MHz does something extra, like writing huge amount of errors into syslog... or at least attempts to do it.

placebo?? rofl

I was responding more to matt about the full device re-flash, not the OP. Doing a full device (OS level) reflash can indeed result in a temporary speedup for the reasons mentioned, especially since a full re-flash also hits the swap partition.

As for 800 not running at 800, or filling a log, that's unlikely. If the chip is set to run at a speed, and it will run at that speed. If it's less efficient to run at one speed vs another (which can be true), the chip won't slow down or adjust it's speed to compensate for it, it will simply draw more power and/or generate more heat.

If he was using an early non/stock kernel that had debugging turned on it may have been doing some extra logging. The path he pointed to though didn't seem to be one of the older ones.

Before I, and perhaps others go a changing our clocks yet again., could you post a link to these reports?

BTW, I have been running mine at 800 for the past month and have had zero issues. It appeared faster and still is faster than stock.

2 questions for the OP.

What kernel did you use?

Did it seem faster when you first overclocked?

...and a bonus third question:

Couldn't this have been discussed in one of the existing overclock threads?

http://talk.maemo.org/showpost.php?p...postcount=1652

http://talk.maemo.org/showpost.php?p...postcount=2231

What is 800mhz specific?


Other then a "perhaps" statement by someone...

From my real world, first hand usage of the zImage800mhz.fiasco image>> http://files.myopera.com/yodude/blog...e800mhz.fiasco

I have had zero random reboots in 28 days or the entire time it was installed.

BTW, to humor this fellow I reflashed back to 600 and guess what?

Everything feels slower and is slower. I'll run it under normal use tomorrow @ 600 and see what is up.
Then before I reinstall the 800 kernel I will plot a route to some obscure address across the country with Sygic Maps and time it. I will do the same at 800 to show the difference.

I don't want to do a second search through Overclock N900 thread - it is too time consuming

But I remember it was related with 800MHz and I remember titan changed frequency because of that to 810MHz (or 815?).

I didn't look in that part of kernel source but it seems to me that there is a high probability that kernel doesn't switch CPU to that frequency.

However, the switching capability may depend from other factors too - again, I had no time to look into that part of kernel code.