eMac 800Mhz -> 1.33GHz conversion

Numbski · Sep 1, 2004

Oh, and another note. These units don't appear to be stymied in the L2 cache department. They all have 512k just like their Powermac cousins. If indeed the multiplier and FSB combinations add up, the only difference at the end of the day is that all of the powermacs are dual cpu now.

Granted, that's a big improvement once we go fully 64-bit and if your applications are threaded. But still.

vga4life · Sep 18, 2004

New stock of refurb emacs...

I've noticed the refurb page on store.apple.com has current-gen 1 GHz emacs for $549 w/ cd-rom and $529 with no optical drives - these have the latest rev logic board (Radeon 9200, USB 2.0) but are clocked down to 1 GHz for edu-market sales.

For $550, it's tempting to pick one up just for hackin' - overclocking, modding into a headless case, etc.

Just a heads up for you modding types.

-vga4life

SEN · Oct 31, 2004

Errors decoding video?

Hello again,

I posted a while ago about clocking my 1ghz eMac up to 1.2ghz. I did have it running at 1.33 and 1.267 but I was experiencing problems with video encoding - blue artifacts would appear randomly throughout the video.

I brought it back to 1.2 and everything seemed fine.

Recently though, I bought Myst Revelation for OS X and I have noticed that
parts of the 'VR' navigation that contain moving video come out as all distorted - at points all the same colour. Maybe a bit hard to put into words, but definitely identifiable when seen.

The video in the VR navigation plays back perfectly across my iBook, Powerbook, B&W G3 and G3 iMac (albeit slow) - however gets distorted on my eMac (which is actually the fastest of the lot).

Wondering if it is a similar problem to what I was experiencing before. Anyone have this game to test out themself?

Brilliant game, BTW

madmaxmedia · Nov 2, 2004

I just bought one-

These have a different CPU- the 7447, although I guess it's only a slight rev over the 7445. I actually bought it thinking it was the prior-year model since it was 1 Ghz, and was very pleasantly surprised to find out otherwise.

Has anyone tried to overclock this one? Or know if the jumpers would be the same? It would be sweet to be able to get to 1.4-1.6 Ghz or so someday, if I'm brave enough to try this (already have put in a 120 GB HD, DVD burner, and fan speed controller with Leo's awesome web page.)

If I could overclock it, then I'm basically getting the $1000 model for slightly more than half (the DVD burner only cost me $50 on EBay, and the 120 GB HD was $60 and is bigger than the 80 GB stock in the Superdrive model.)

vga4life said:
I've noticed the refurb page on store.apple.com has current-gen 1 GHz emacs for $549 w/ cd-rom and $529 with no optical drives - these have the latest rev logic board (Radeon 9200, USB 2.0) but are clocked down to 1 GHz for edu-market sales.

For $550, it's tempting to pick one up just for hackin' - overclocking, modding into a headless case, etc.

Just a heads up for you modding types.

-vga4life

wernerru · Nov 2, 2004

madmaxmedia said:
These have a different CPU- the 7447, although I guess it's only a slight rev over the 7445. I actually bought it thinking it was the prior-year model since it was 1 Ghz, and was very pleasantly surprised to find out otherwise.

My 7445 is still running at 1.6ghz, and i just did a friends 7447-based emac, and kicked up to the same 1.6ghz. the great part is is the 167 fsb; we could up that as well, and take it to 2.0ghz. we did a regular oc to 2.0ghz, but it was unstable after about a few hours of semi-intensive work. it's rock-solid at 1.6ghz, running folding@home, which bashes the processor harder than any benchmarking utility.
best of luck
russ

madmaxmedia · Nov 2, 2004

Awesome, thanks! So would the directions for the 7445 work exactly the same for the 7447?

Great to know that I can kick my eMac up later, to better than new specs! (it already works great for me so far at 1 Ghz.)

wernerru said:
My 7445 is still running at 1.6ghz, and i just did a friends 7447-based emac, and kicked up to the same 1.6ghz. the great part is is the 167 fsb; we could up that as well, and take it to 2.0ghz. we did a regular oc to 2.0ghz, but it was unstable after about a few hours of semi-intensive work. it's rock-solid at 1.6ghz, running folding@home, which bashes the processor harder than any benchmarking utility.
best of luck
russ

madmaxmedia · Nov 2, 2004

While it's better to be safe than sorry, here are some links I found regarding CRT discharge. I didn't discharge my CRT when I disassembled my eMac, but I left it unplugged for awhile just to be safe.

http://www.applefritter.com/thefritter/13/drwebster.html

So, if the danger is so low, why does Apple recommend discharging the CRT? Simple: lawyers. If Apple didn't give this advice, and someone simply claimed injury from a shock, then they'd have a problem, regardless of the facts. Plus, if you get zapped, maybe you'll slice your hand on something in reaction. It's a simple act of CYA for Apple to recommend always discharging the CRT.

A reasonable case could actually be made for why you should advocate *not* discharging a CRT routinely. If you require that everyone do so, then you're asking that everyone deliberately expose him- or herself to high voltage. One slip of the ground clip, and you get the honor of being the discharge path. If you really believe HV to be so dangerous, does this sound like good advice? And if you do fear an implosion, then does it make sense to require everyone to scrape a tool under the anode cup, potentially scoring the glass and weakening it to the point of causing an implosion?

And even if a discharge itself causes no bodily harm, it sure can cause delicate components on the circuit board to fry, depending on the particular path the discharge current happens to take.

So, here's a perfectly rational, safe policy: If you don't have to work on the high voltage supply, keep your cotton-pickin' mitts off of the high voltage circuitry. All the components there are very well insulated. And of course, always work on the Mac with the ac power disconnected (not just switched off; pull out the cord). If you want to minimize the chance of getting an unpleasant jolt, just let the thing sit overnight.

http://www.mail-archive.com/compact.macs@mail.maclaunch.com/msg12553.html

> Let's say if by accident my hand brushed up against the neck of the
> CRT, would I get a shock?

As long as you aren't working on the thing with power on, you're fine.
There are no exposed high-voltage parts on the crt. All the HV is *very* well
insulated. That's why you should ignore the standard advice to routinely discharge a compact mac's crt. You have to expose yourself to the HV nodes to discharge, and that just doesn't make sense if you're not going to do any work on the HV circuitry.

> How long should I wait for the CRT to discharge on its own if I don't
> use a tool?

Leave it unplugged overnight. Even without the fabled "bleeder resistor" in the
flyback transformer, the crt will discharge enough.

Really, the compact mac's cute little crt is not a thing to be feared.
Don't allow the irrational (well-meaning, yes, but still irrational) warnings of others frighten you away from fixing these little guys. I hate to see a compact mac needlessly turn into landfill.

madmaxmedia · Nov 3, 2004

Overclock your ATI video card too!

Here's an interesting program to overclock ATI video cards, all via software! (no soldering or even disassembling your computer.) It works for at least the most recent eMac (Radeon 9200)-

http://thomas.perrier.name/software/ATIcceleratorII.html

Here are some feedback reports from people who have tried this-

http://www.xlr8yourmac.com/Graphics/aticelleratorII_reports.html
http://morg.free.fr/atiacc2/index.php?lg=uk

It seems that increasing around 10% or so shouldn't be a sizeable risk. It's not too significant or anything, but it's an easy mod. Plus if you can get 10% higher FPS on Halo, etc., it might be worth it... ;-)

wernerru · Nov 4, 2004

madmaxmedia said:
Awesome, thanks! So would the directions for the 7445 work exactly the same for the 7447?

Great to know that I can kick my eMac up later, to better than new specs! (it already works great for me so far at 1 Ghz.)

Yeah, the 7447 as far as i remember went exactly the same as the 7445, just the FSB jumpers were in a different order (167 instead of 133). so a jump to the 12x like i did to go from 1.0 to 1.6, would take you to 2.0, which might not be stable, nor advisable

. I'd say do a moderate jump, maybe to 10, which is what everyone is doing on the 133fsb.

madmaxmedia · Nov 4, 2004

Awesome, thanks for all the great information!

In reviewing the jumper settings-

http://www.freescale.com/files/32bit/doc/data_sheet/MPC7455EC.pdf (pg. 47)
http://www.lbodnar.dsl.pipex.com/eMac/eMac-upgrade.html

It looks like the 2 easiest overclocks for me would be 8x and 9.5x.
8x (giving me 1.3 Ghz) would only involve adding 1 jumper.
9.5x (giving me 1.58 Ghz) would only involve removing 1 jumper (great!)

As long as those are stable settings (I assume they are if 10x is stable), I'm thinking 9.5x would be better for me. I think this the speed you overclocked your friend's eMac at?

I have soldering experience but not much. I think I can handle removing 1 jumper, but would rather not have to remove and add multiple jumpers (giving me 5x as many opportunities to screw up.)

How hot does your overclocked eMac run? Like Leo, I added a fan controller to reduce the noise, but I'm wondering how low I can go if I overclock at 9.5x...I think the 7447 is probably comparable to the 7445, and Leo said the following about his overclocked eMac-

To cut the story short - you can slow down fan to the point where you cannot even hear it rotating and eMac would not care at all. Remember, this is with overclocked CPU, fast hard drive and 1GB or RAM and under day and night 100% load. If this is not the best computer hardware engineering, than what?!

I don't need to go so low as to not hear the fan. I don't know if he is using a bit of hyperbole in his statement though.

Thanks again,
Steve
(having lots of fun with a $550 eMac!)

wernerru said:
Yeah, the 7447 as far as i remember went exactly the same as the 7445, just the FSB jumpers were in a different order (167 instead of 133). so a jump to the 12x like i did to go from 1.0 to 1.6, would take you to 2.0, which might not be stable, nor advisable . I'd say do a moderate jump, maybe to 10, which is what everyone is doing on the 133fsb.

wernerru · Nov 4, 2004

madmaxmedia said:
Awesome, thanks for all the great information!

As long as those are stable settings (I assume they are if 10x is stable), I'm thinking 9.5x would be better for me. I think this the speed you overclocked your friend's eMac at?
(having lots of fun with a $550 eMac!)

Yup, i took it to the 9.5, since soldering on dry pads is a huge pita. The temp really didn't increase much at all on either eMac tho. i'm almost thinking of getting a refurb myself, and oc'ing it to just have another mac

topgunn · Nov 5, 2004

madmaxmedia said:
Awesome, thanks! So would the directions for the 7445 work exactly the same for the 7447?

Great to know that I can kick my eMac up later, to better than new specs! (it already works great for me so far at 1 Ghz.)

I have both a 2nd and 3rd generation eMac. The 2nd gen was a 1GHz that i bumped up to 1.27GHz and the 3rd gen has remained at 1.25GHz, but not by choice. The first day I got it, I ripped it open to see if the layout of the logic board was similar enough to the 2nd gen to figure out the location of the PLL multiplier resistors. It wasn't and I have had zero luck trying to find them so far.

If anyone has any information that may help me find these pesky PLL resistors or even the FSB resistors, I would greatly appreciate the assistance.

Here is a link to some pictures I took of the logic board. http://www.texasgunns.com/emac . The first picture is where I would have expected to find the jumpers if the layouts between the 2nd and 3rd generations were similar.

Thanks,
John

madmaxmedia · Nov 5, 2004

Hmmmm, hopefully wernerru will be able to tell us exactly where they are.

A 1.25 Ghz CPU with 167 Mhz bus should mean a 7.5x multiplier. According to Leo's page (as well as the Motorola manual), the pattern of the jumpers should be '+ + + - +', where '+' means connected by a resistor.

BTW, I made a mistake regarding the 9.5x mod. It actually involves adding a jumper, in addition to removing one. Still not too much, and less work than 10x. It doesn't actually look that difficult to add a little solder to connect the jumpers.

topgunn · Nov 5, 2004

madmaxmedia said:
A 1.25 Ghz CPU with 167 Mhz bus should mean a 7.5x multiplier. According to Leo's page (as well as the Motorola manual), the pattern of the jumpers should be '+ + + - +', where '+' means connected by a resistor.

Yes, both my eMacs were factory set at a PLL multiplier of 7.5 and according to Freescale the jumper configuration is the same for both the 7445 and the 7447. The 2nd gen eMac is easy in that it has 5 jumpers in a wide open area that are in the same order as the PLL jumpers from the datasheets. However, not all macs have 5 resistors to change the multiplier. The 167MHZ FSB iMac uses 8 resistors to select the multiplier. Some older G4's only used 4. 98% of the pads on the PCB are occupied. There are probably on 4 or 5 locations where there are groups of unoccupied pads. This leads me to assume that one of the areas is the one that I need to concentrate on.

topgunn · Nov 7, 2004

madmaxmedia said:
Hmmmm, hopefully wernerru will be able to tell us exactly where they are.

Do you have any pictures of the jumper configuration of your eMac? If we look in the right areas we should be able to see some differences. Once I know which ones control the multiplier, I would be willing to do some trial and error testing.

Mechcozmo · Nov 7, 2004

I just read the whole thing. Anyone wanna take a guess at how you could overclock an 800Mhz iMac? See my sig for more details on it. I'd like to at least widen the gap between it and obsoleteness. Very cool work... I'm gonna see if I can boost my brother's and sister's eMacs.

madmaxmedia · Nov 7, 2004

topgunn said:
Do you have any pictures of the jumper configuration of your eMac? If we look in the right areas we should be able to see some differences. Once I know which ones control the multiplier, I would be willing to do some trial and error testing.

Unfortunately I don't. I'm hoping we get good info from wernerru, since he has modded the exact same model as ours.

If we had no such info, I don't know if it would be too safe to try making changes without knowing exactly which are the right jumpers. Although it might be possible by process of elimination to find the exact right set.

Now I see that you have a 1.25 Ghz eMac. So if we compare photos and find which jumpers are different between our boards, we should know (and combined with the proper jumper settings for each of our multipliers.)

If we can't get any other info, I'd be willing to take apart my Mac and taking some photos. Let's give it a few days to see what comes up?

madmaxmedia · Nov 7, 2004

Mechcozmo said:
I just read the whole thing. Anyone wanna take a guess at how you could overclock an 800Mhz iMac? See my sig for more details on it. I'd like to at least widen the gap between it and obsoleteness. Very cool work... I'm gonna see if I can boost my brother's and sister's eMacs.

Search around on Google. I'm almost positive I saw overclocking directions for a G4 iMac, not sure if it was in English though or what the clock speed was. I think the directions I saw involved removing the heat sink in order to get to the jumpers.

brap · Nov 7, 2004

madmaxmedia said:
Search around on Google. I'm almost positive I saw overclocking directions for a G4 iMac, not sure if it was in English though or what the clock speed was. I think the directions I saw involved removing the heat sink in order to get to the jumpers.

Sure you don't mean this post, in this very thread?

SEN · Nov 7, 2004

iCook

http://www.swieskowski.net/icook/

"iCook is a small OS X kernel extension that allows simple overclocking..."

Is this kind of thing possible with other Apple models?

(turns out my graphics problems were/still are Myst, not the Mac)

jared_kipe · Nov 7, 2004

I made my girlfriend's (ok it's really mine) emac go from .8GHz to 1.4GHz and it booted fine. After like 30 min in Tiger woods (computer playing itself) it would die. So clocked it down to 1.33GHz and it would last 1 hour of greensome. So I (she) had to settle for 1.27GHz and a ATI video overclocker.

Mord · Nov 8, 2004

SEN said:
http://www.swieskowski.net/icook/

"iCook is a small OS X kernel extension that allows simple overclocking..."

Is this kind of thing possible with other Apple models?

(turns out my graphics problems were/still are Myst, not the Mac)

only cpu's made by ibm with that feature so thats 750fx's and g5's but no one has tryed on a g5

madmaxmedia · Nov 8, 2004

brap said:
Sure you don't mean this post, in this very thread?

LOL, I didn't remember that post. I had also seen something else from the web somewhere...

"iCook is a small OS X kernel extension that allows simple overclocking..."

Is this kind of thing possible with other Apple models?

It's unlikely since this type of software clocking is built into notebook computers for energy conservation (besides being chip-specific.) I doubt any of the desktops have this ability.

Mord · Nov 8, 2004

madmaxmediaI doubt any of the desktops have this ability.[/QUOTE said:
all g5's have it and mosty powerbook's/ibooks

wernerru · Nov 10, 2004

madmaxmedia said:
Unfortunately I don't. I'm hoping we get good info from wernerru, since he has modded the exact same model as ours.

madmaxmedia, i tried to find the pictures i took when we did it, and i can't seem to find them tho. My friend now lives on the other coast, and he's not so tech-adept, so i can't ask him to take it apart and tell me. Sorry

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