68060 Overclocking

[musojon74]

When just running at 50mhz, do this things run cool enough without heatsink / fan in a normal desktop case a1200?

[Hewitson]

Originally Posted by musojon74

When just running at 50mhz, do this things run cool enough without heatsink / fan in a normal desktop case a1200?

Yes a fan/heatsink isn't needed for 50mhz operation.

[Paradroid90]

I have a apollo 1260 running at 66MHZ with heatsink and fan in a Power Tower case.

All the work was done PG and his service is excellent and i have had not problems with the card since the work has been done.

Had major problems with the card before.....Just ask Zetro.

But PG is the man to ask.

Not tried the card in a Standard A1200 case but the ventilation i think would be problem and increased power draw required which has already highlighted by Zetro and Alexh.

Hope this Helps!!

[lvd]

The abovementioned mask 71E41J is the latest mask with all vital bugs corrected and also is a shrinked version of previous ones (0.32um, older were 0.5um afaik). So it is obvious it can run with higher frequencies with lower heat dissipation.

The 040-060 boards itself, I think, should run 80MHz smoothly since they can run 040 at this frequency.

80MHz fed to 040 yields to 40MHz bus and core frequencies, while the same 80MHz fed to 060 yields to 80MHz core frequency and 40MHz bus frequency. This is probably why 50MHz 060 is slower accessing chipram than 40MHz 040.

[alexh]

When overclocking problem comes down to the RAM controller.

The fastest SIMMS available had 50ns parts on them.

Originally Posted by Wikipedia

The generally quoted number is the /RAS access time. This is the time to read a random bit from a precharged DRAM array. The time to read additional bits from an open page is much less.

When such a RAM is accessed by clocked logic, the times are generally rounded up to the nearest clock cycle. For example, when accessed by a 50 MHz state machine (i.e. a 20 ns clock), the 60 ns DRAM can perform the first read in 3 clock cycles, and additional reads within the same page every clock cycle. This was generally described as "3-1-1-1" timing, as bursts of 4 reads within a page were common.

If the wait states of the RAM controller are not configurable and you up the clock rate to 80MHz (assuming the CPLD/FPGA will operate that fast), it will expect data to be valid when it is not.

[alexh]

The RAM controllers on *some* of the phase5 products have configurable RAM timing.

They have the command setmemmode.

My 68000 timing diagram knowledge is a bit rusty, the doc for setmemmode talks about "nowaitstates" which but I am unsure 100% sure what a "wait state" means in this case WRT to clock cycles.

[rkauer]

I did this to my crappy MBX1230@56MHz (hey, 12% over the normal speed is not that much, but I had to set the 128Mb SIMM/70ns memory to "fake" 80ns).

Put two thermaltake-glued heatsinks in the 030 & FPU, use the old trapdoor as a screen to a loudspeaker telly (all painted in white, like the 1200 itself), and put a notebook VERTICAL fan inside the case, blowing air towards the whole accelerator. I catch the heatsinks from a northbridge/southbridge kit.

That was a good thing, the fan also cool the SIMM (who ran pretty hot, too).

Pictures, anyone want?

[musojon74]

Hi again all!

Well, I got my new Blizzard 1260 from BinoX - fantastic, thanks again!

I've fitted it into my desktop 1200, started up - all good! No trapdoor on just in case! Thought it was not really running that quickly - Gloom still very slow, even after running Cyberpatcher.

I've now found out after it crashed and was running rather hot, that I've unintentionally been overclocking! It's got a 66.66mhz crystal in!

Do I just buy this from Amigakit: 50Mhz Crystal Oscillator (14-pin DIL) ? or do I need an 8 pin DIL?

Sorry, I'm obviously more of a newbie than I thought!

Thanks

--edit--

OK sorry, I was stressing out above! I've looked at the crystal socket on my board, and it's got 14 holes, 7 each side, the corner ones look slightly different. So I'm guessing I just need to buy a 14 pin DIL crystal at 50Mhz to ensure I can use the 060 in my desktop without extra cooling.

The chip is an X68060RC50, this will run OK without cooling at 50Mhz in a desktop won't it?

Cheers!

[CU_AMiGA]

csmk3 seems to be really good with overclocking. i have the e41j 060 overclocked at 66mhz and no problems whatsoever. the 060 is really cool, although i have fan onit anyways!

[DDNI]

musojon is the memory in the card running at 60 or 70ns?

[musojon74]

Err, I'm not sure, I'll spin it up and have a look at cpu060 and stuff. (I can only run it 10 minutes at a time!) Have a 50mhz crystal on route 14 DIL.

Cheers!

[musojon74]

OK not sure, how do I check? Interestingly, the Cybersnooper program will not run, it just guru's every time.

I am more out of touch with this stuff than I thought!

--edit-- at least I found out that it's a revision 1 cpu from cpu060.

[Hewitson]

Originally Posted by musojon74

Err, I'm not sure, I'll spin it up and have a look at cpu060 and stuff. (I can only run it 10 minutes at a time!) Have a 50mhz crystal on route 14 DIL.

Cheers!

10 minute? Put a fan on the bloody thing!

[musojon74]

I'm looking into cooling options now, difficulty is the fact that a SIMM covers part of the CPU as Nightlord mentioned above.

The Amiga will run for longer than 10 minutes to be clear, but I have touched the CPU and it feels quite hot. To be fair I do not know how hot these things can get safely. It doesn't seem to have crashing issues.

I shall fit the 50mhz crystal first, so I can have some fun, and then look at the cooling options - will just a fan be enough for a rev 1 xc?

Originally Posted by Braddo

10 minute? Put a fan on the bloody thing!

[Hewitson]

At 50mhz a fan is not needed, however the earlier revisions will run quite warm so it certainly wouldn't do any harm to fit one.

I do not recommend using that card AT ALL @66mhz with no fan.

[musojon74]

ok now i understand! Takes a while! I will await the new crystal before using again! Do you blow air into or suck air out of the case with your fan? I assume you pull the power off the floppy connector? Do you use a heatsink as well as a fan?

Sorry that is all of my questions!

Cheers!

Originally Posted by Braddo

At 50mhz a fan is not needed, however the earlier revisions will run quite warm so it certainly wouldn't do any harm to fit one.

I do not recommend using that card AT ALL @66mhz with no fan.

[musojon74]

OK, I found an old PC fan from a pentium 3. I've hooked it up to a multi power adapter, so it's got its own supply! I then sellotaped it very close to the CPU, blowing air onto it. How awful is that? I then played gloom for 10 minutes, played some mp3s and mods, then played quake for 10 minutes. Quickly switching off and checking the CPU, it was only slightly warm to the touch, so I'm thinking it's cooling it enough.

Obviously, I'm now looking for a slightly better way to mount it! But for you all to laugh at, here's a pic.


That seems to keep it nice and cool!

[Magno Boots]

What voltage is the fan?
I've run a 12v of the floppy connector previously without problems.

As for mounting the fan, you could cut a tight square in the trapdoor cover and just squeeze the fan partly into it. Some hot glue and your away!

Looks like you have the standard rubber feet still attached, so you will need some larger ones. PM if you need any.

[musojon74]

Hi there! Yes it's a 12v one, I'd like to run it off the floppy connector once I'm happy it's cooling enough, and it does appear to be. Is it 12v off that though? I'd like to ensure the fan is at high enough speed.

Will definitely look at cutting the trapdoor, will be nice to fix with a more sensible method other than sellotape! I just wasn't sure initally that I was going to get enough cooling, but after hammering Q2 and Doom, cpu was only barely warm.

Cheers! Have pm'ed you regarding feet

[Hewitson]

I recommend using double-sided adhesive pads to mount the fan. You can use 2 or 3 of these to build up the height of it slightly as you do want a small gap between the fan & CPU so that the hot air can escape. As for powering the fan, I'm not sure about your card but mine has points to solder a wire for both 5v and 12v power.