Overclock Speeds?


Turnip

Member
Joined
May 21, 2007
Messages
165
I assumed there would be a thread with people posting the overclock speeds they can get but I cant seem to find one. Is there one? I wanna know what sort of range we can expect our maximum speed to fall within.

If theres not one please feel free to post your speed here.
 
Turnip said:
I assumed there would be a thread with people posting the overclock speeds they can get but I cant seem to find one. Is there one? I wanna know what sort of range we can expect our maximum speed to fall within.

If theres not one please feel free to post your speed here.

There is an overclocking thread in one of the new subforums (hardware hacking)

http://www.gp32x.de/board/index.php?/topic/53863-overclocking-and-overvolting/
 
Last edited by a moderator:
Since I don't want to insert my hardware ignorance in that thread I'll just ask here; can someone explain what over/under volting is exactly and how it relates to overclocking?
 
Eniko said:
Since I don't want to insert my hardware ignorance in that thread I'll just ask here; can someone explain what over/under volting is exactly and how it relates to overclocking?
This has been explained in an older thread quite well, cba to dig it out though.
 
Last edited by a moderator:
kuru said:
This has been explained in an older thread quite well, cba to dig it out though.
Couldn't find it or I wouldn't have asked. All I found was a thread discussing overvolting briefly in regards to overclocking but didn't explain any of it, and that thread then devolved into talk about automatic clock adjustment.
 
Last edited by a moderator:
Higher voltage means more current runs through the chip. This in turn makes the chip act stronger, and frequency that isn't stable at lower voltages might be at higher. However, more current means more heat, and heat, can permanently fry your chip. There is also an issue of electromigration, which increases as you bump up the voltage. This can cause damage even if it hasn't overheated. Most notable example, some Intel P4's had a N.S.D.S. thing going on. (Northwood Sudden Death Syndrome) N.S.D.S. only happened if you went over a certain voltage. This voltage is usually said to be 1.6v or just above... Off course, the chip, and it's electrical characteristics are nowhere near in relationship with the Intel Northwood, so when possible electromigration becomes an issue is anyones guess. Of the top of my head, I'd say what ever the manufacturer says is OK for the fastest chip's made in the same process + an extra 10% "should" be safe. This since faster chips really are identical, they have just been rated for higher speeds by testing, also known as "speed binning."

(The phrase "makes the chip act stronger" is really not a proper description of whats going on. It's an attempt to explain what i cant really describe properly, due to lack in language skills. Whats really going on is that the difference between high and low phases are increased. A CPU is ideally switching state uniformly over the whole chip, but in reality its more of waves that rips past the silicone and each wave is one tick of the frequency. If you want a better explanation you'd have to get someone with a better English ability then mine. Sorry.)

Anyway. Overclocking always increase heat output. If your able to drop voltages and overclock you'd see first a drop in temp, and then a raise from that lower baseline. This is why generaly speaking, overclocking always voids your warranty. Realistically nobody can tell if you overvolted or not on the chip, and as such some people undoubtedly will fry there chip, and come back to claim a warranty. Even tho this is possible, there are some strong incentives not to do so. For one, you broke it. You knew overclocking could damage your chip, and overclocking / over volting can do permanent damage that grows worse over time leaving you with a dead chip weeks, or months after you actually did any overclocking. Another reason is simply die to it being illegal, should anyone figure it out, they could actually press charges. Perhaps that ex girlfriend that was getting neglected when you were trying to get another 2MHz out of the chip will testify against you. A worst case scenario lands you in jail for having broken the darn thing, and trying to get a false claim accepted. Very unlikely, but... And finaly. If people who overclock and break there toys end up getting "free" replacements, that means anyone who buys a Panda actually have to pay for the broken one he had, since the money for producing it has to come from somewhere. Just don't do it. Claim warranty, on a item you broke, that is.
B!
 
Over/undervolting refers to the act of increasing or decreasing the voltage from the base voltage. Transistors are (basically) switches. As you increase the clock speed, those switches need to flip faster and faster. Eventually you reach a point where they're flipping so fast, there's just not enough energy to flip them completely every time, and that's where errors happen and the system crashes. By increasing the voltage (overvolting) you increase the energy being used to flip the transistors on and off, which in turn decreases the chance that a transistor won't flip all the way. Unfortunately, this has the effect of using up more battery power, increasing heat from lost energy, and a greater risk of breaking the CPU (think of it like flipping a switch so hard the switch breaks off).
On the flip side, you can decrease the voltage (undervolt), thus reducing the energy used to flip the transistors on and off. Again, just like with increasing clock speed, eventually you reach a point where the transistors can't flip properly anymore and the system crashes, but you can reduce the clock speed to compensate. By undervolting and reducing the clock rate, you will use less energy, waste less energy, and experience longer battery life.

edit: :ph34r:
 
So if my Pandora runs stable at 850Mhz on whatever the default setting is, is it likely that it will run stable at 600Mhz at a lower voltage setting. And how much longer would the battery be likely to last?
 
Pleng said:
So if my Pandora runs stable at 850Mhz on whatever the default setting is, is it likely that it will run stable at 600Mhz at a lower voltage setting. And how much longer would the battery be likely to last?


Default CPU speed is 500Mhz. Like Craigix mines stable at 850Mhz.

A nice little message pops up when you change CUP speed, it warns of possible house fires and explosions. :)
 
Last edited by a moderator:
Pleng said:
So if my Pandora runs stable at 850Mhz on whatever the default setting is, is it likely that it will run stable at 600Mhz at a lower voltage setting. And how much longer would the battery be likely to last?

It's not a huge amount, you might gain an hour playing about with CPU speeds. The LCD is the real power hog.
 
Last edited by a moderator:
Pleng said:
So if my Pandora runs stable at 850Mhz on whatever the default setting is, is it likely that it will run stable at 600Mhz at a lower voltage setting. And how much longer would the battery be likely to last?
OPP3 is the default and OPP2 is specified for 250MHz. It's _extremely_ unlikely to reach 600MHz at OPP2.

Basically the Pandora undervolts automatically. When you raise the CPU clock above 550MHz, you undervolt, because it would have to increase to OPP4 according to specs, but it doesn't. It's fixed at OPP3.
 
Last edited by a moderator:
Anyone NOT able to get to at least 750?

@Sarlix, does that message also mention warranty? I guess what I'm wondering is does the overclock software automatically overvolt if you tell it to go to high and then warn you about house fires/warranty because of the required overvolting? I would hope that you'd have more control on how it overclocks.
 
^ Taking various info and Jeff's post in that other thread into account, I suspect that anything up to 900MHz is at OPP3.
 
As mali said, currently it is fixed at OPP3. So even when you run it at over 500Mhz by TI's spec your undervolting as it should be at OPP4 or 5. (OPP is voltage)
But OPT has guaranteed them to run at at least 600Mhz, at OPP3.
Some makes and model of chips overclock better than others. And within the models there will be variations on what you can achieve.
The sort of heat generated to OPP5 compared to OPP3, and the likely hood of damage compared to it just being unstable, therefore you knowing that you can't run it at that speed is very low. These ARM chips seem to be very good overclockers. IMO

I don't even think OPT was even going to mention warranty, as they felt the chance of damage was so low, but there was such a debate over it, they just said ok lets say 'this' it will get people of our backs.

Anyway I think it would be nice to just have a thread that just has the highest stable speed at the current OPP3. As we currently can not change the OPP.
 
It's interesting how everyone is talking about overclocking... I want to UNDER clock it as much as possible with stuff still working. I hope emulators and programs get optimized enough that we don't need to have it at 850mhz! (note: I do know that N64 and stuff is probably impossible for that)
 
lets make a deal, devhace. If my pandora won't clock past 700 and yours will, I'll trade you :p
 
Back
Top