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SkyCapt's picture
Joined: 2017 Jan 11
Insane graphics acceleration & 4GB RAM on PowerMac G4 Mirror Door 2003

This is fresh, nobody else's yet made this happen. I create an obvious two fold increase in graphics render/display speed when I combine these 2 things: greater than 2GB RAM plus changing the firmware's model code from G4 to G5. I already have a G5 graphics card in my Mirror Door '03, the ATI Radeon 9600 Pro 64MB vram. And I have G5ish RAM 1GB per module 467MHz CASL2.5 (declared to be CASL3.0 at least 400MHz). The acceleration takes effect in OSX 10.2.7(G5) thru OSX 10.4.11 - not in 10.2.8(G4) nor in OS9 nor OSX 10.5.8 Leopard.

I'll describe more specifically what I'm doing, and, while I've already witnessed past acceleration due to my RAM and my G5 graphics card, I don't know yet the specifics of how and why this here newest two-fold speed increase is happening. This comes as such a surprise because I thought I had been pushing the hardware as fast as it could go. fyi my screen resolution is 1920x1200.

There's a wide range what could be causing this additional two-fold leap up. I'll hailmary a first best guess. The OSX+CPU recognizes only 2GB RAM. The RAM in excess of 2GB (right now I'm succeeding with 3GB total, 4GB isn't required) RAM is available to the GPU/AGP without CPU speed taxation. The CPU could write/read the excess RAM via bank selecting, or via specific commands to the memory controller. The GPU can access the excess RAM faster than it can its own 64MB vram. At 1920x1200xMillions of color, the 64MB vram can hold only about 7 frames, less than 7 after factoring in texture data and GPU commands etc. This new two-fold speed increase basically is the result of gaining the equivalent of 1024MB-2048MB superaccelerated vram. System Profiler now says my computer is a "Power Mac G5" but with a G4 CPU. I dedicate this discovery to ArsTechnica and everybody else who Dropped The Ball (..."there is no proof!" spoken like the trade federation in Star Wars Episode I)


SkyCapt's picture
Joined: 2017 Jan 11

This project requires the PowerMac G4 MDD2003 computer, the MDD2002/FW800 computers are not good enough because they can't install more than 2GB total RAM and, the MDD2003 has a more advanced memory controller which accepts 1GB RAM per slot therefore up to 4GB total. Apple's "Setup Guides" explicitly state 512MB per slot MDD2002 vs 1GB per slot MDD2003. **Are there more G4 models in which greater than 2GB RAM can be attached? ?

I haven't yet tested what if any acceleration happens with my G4 graphics cards (I have the MDD's native ATI Radeon 9000 Pro 64MB vram and the MDD's other native option Nvidia GeForce4 Ti 4600 128MB vram). Instead I'm using the ATI Radeon 9600 Pro 64MB vram, an OEM G5 edition. It's already been like TWICE the card the 9000 was, so I've little interest in the G4 cards even if they are supported in OS9 ... the 9600 is not utilized when booted in OS9.

G5 graphics card required a trick to make it function in this G4 computer. Specific info has circulated widely, the G5 card needed two of its AGP pins disabled, pin #s A3 and A11.

The main memory bank could take a lot of explaining. Start with knowing you need modules with 1GB capacity in each, test them installed solo one at a time and run loads looking for crashing. See if you can, still with the G4 machine id in firmware, sort your modules by their apparent performance speed, not their profiled speeds. You need 3 modules of preferably the best speed which can all work together without crashing in the three ram slots nearest the cpu.

RAM exceeding 2GB is NOT recognized by the firmware nor any version of OS X nor OS 9. Excess RAM is however recognized by the AHT (v2.0.2-v2.1.0) for PowerMac, where you see "3GB" or "4GB" colored red.

AHT software on the 10.2.7 G5 disc, AHT v2.1.0 looks more appropriate for the Mirror Door 2003 than the one supplied with Mirror Door (v2.0.2). But it turns out AHT can't run with the Mirror Door in G5 machine id mode, you must switch to G4 machine id or use an edited AHT disc/image to run AHT. The AHT v2.1.0 must be edited to run on Mirror Door. Fortunately, such an edited AHT has been posted on mg for a couple years, the incredibly awkward "AHT All-In-One beta1" has all 6 versions of AHT for mirror doors, on one bootable disc and a menu for choosing them.

This "insane" graphics/video acceleration (of thread topic) can be seen, and without modifying the firmware, by booting into the G5-specific version of OSX 10.2.7 (Build number 6S80) found here:

Unfortunately, unless you use a G5 to do the 10.2.7 install and then offer that disk to the Mirror Door, or edit the 10.2.7 Install Disc (see next link below) -- you are best-off changing your Mirror Door's machine id in firmware from G4 ("PowerMac3,6") to G5 ("PowerMac7,2") - some firmware instructions included in this link:

I havent offered how to make the firmware's machine id become semi permanent, I could do that later, here below.

After updating OS X 10.2.7 (G5) to become 10.2.8 (G5) (build number 6S90) or if applying a QuickTime update, the graphics slows back down to G4-video mode, if the firmware's machine id is G4. So adopting the counterfeit G5 id is what allows OSX 10.2.8(G5 build) to get 'insane' too.

OSX 10.2.8 had two different builds for G4-video vs new-video. In OSX 10.3 it became one OS build/install with video mode still disguised by firmware's machine id. When Apple/internet tried to discredit/destroy OSX 10.2.7/10.2.8 for G5 by posthumously naming it "Smeagol" (nee Jaguar) and saying it had been (successfully) recalled, I thought they were trying to hide something rather than be helpful to everyone. Now I'm certain. The G5 graphics card lock-out, needing to disable two AGP pins, feels the same way. They prevented G5 graphics cards from operating in G4 because they're hiding how good they can be.

note: Always remain aware of the performance and limitations of your Mirror Door's air cooling system. Increasing performance such as the topic of this thread, comes with increased demand for cooling, and thus may necessitate improvements to one's cooling system, and hopefully never involve hardware damage due to heat improperly regulated.

SkyCapt's picture
Joined: 2017 Jan 11

are those crickets I hear?

In a few days I'll take down my "AHT All-In-One beta1" & put up version 0.2 which will be for PowerMac G4/G5 only.

The concept in beta1, ALL new world PPC AHT on one CD, requires a firmware driven menu (a ton of programming work) and begins to exceed CD size so would require a DVD (not legacy friendly) and a ton of work in general. beta1 diagnostics driven menu is flawed in that even tho my hardware runs all relevant AHT v1 with a single v1 diag & all relevant v2 with a single v2 diag, OTHER hardware exists where this is not the case and each AHT should utilize the diags which comes with them (requiring a firmware driven menu to load like that). But on the PowerMac Mirror Door 2003 I still want TWELVE versions of AHT , so the very easy diagnostics-driven AHT-AIO-CD/image will live on as a more completed looking version 0.2 made for PowerMac-only. It'll have this:

A) AHT v2.1.0 on G4 (ignores hw id re G4/G5)
B) AHT v2.1.0 on G5 (ignores hw id re G4/G5)
C) AHT v2.0.2 on G4 (ignores hw id re G4/G5)
D) AHT v2.0.2 on G5 (ignores hw id re G4/G5)
E) AHT v2.0.1
F) AHT v2.0.1 (edited to be RAM-friendly)
G) AHT v2.0.0
H) AHT v2.0.0 (edited to be RAM-friendly)
J) AHT v1.2.7
K) AHT v1.2.7 (edited to be RAM-friendly)
L) AHT v1.2.6
M) AHT v1.2.6 (edited to be RAM-friendly)

The preferred AHT for MDD2003 will be choice A and gotten without "wiggling the mouse'. AHT is offered way back to v1.2.6 because, never forget, up until only a couple years ago, from 2003 to 2016, the internet was telling people that v1.2.6 was the correct version for ALL "Mirrored Drive Doors" systems, AHT v2.0.2 was nowhere to be found because it was married to a 4GB disc image, AHT v2.1.0 was nowhere because no one would have suggested running G5 AHT on the G4-MDD.

So, NOT having to partition, install separately, or burn TWELVE aht versions, but instead have all 12 at one's fingertips with one partition... sweet!

SkyCapt's picture
Joined: 2017 Jan 11

New AHT-AIO for PowerMac (G4) is almost finished, just documentation and more testing to do, see it in about one week. It is stinking awesome. It has 7 AHTs:

A) 2.1 for G4
B) 2.1 for G5
C) 2.0.2
D) 2.0.0
E) 2.0.1
F) 1.2.6
G) 1.2.7

All seven can run on any hardware and all seven contain numerous bug fixes to the AHT itself. The nastiest "bug" (Apple did it deliberately but disguised it as an honest mistake) bug exists in all AHT v1.2 thru v2.1+ for all hardware, this "bug" displays the error message "invalid memory access" without really performing AHT. Because of the seriousness of this bug fix, I've decided to not even include the choice of running unmodified-AHT from the AIO image, even tho unmodified-AHT can be found inside the AIO image. Also, the idea of AHT v2.0.2 for G5 was dropped because i found it has no meaning, the G5 test suite file found on apple's G4 v2.0.2 disc is just an older version of the one on the AHT v2.1 and this older version G5 test requires AHT v2.1 regardless.

When AHT crashes saying "invalid memory access", it's a lie if you believe you have a bad DIMM. This is what AHT does when it encounters a DIMM with "unsupported (within AHT)" SPuD codes. The SPuD is the tiny (less than 5mm X 5mm square) chip in one corner of the DIMM. I have (and use) DIMMs which crash AHT v1.2 thru v2.0.1 but don't crash v2.0.2/v2.1 ... but 2.0.2/2.1 don't contain the bug fix rather they contain "support" for more variety module types. THIS below is AHTs lawsuit-inviting bug, and its fix, wrong with All AHT sourcecode:

AHT bug
Search the AHT_script file for ascii string "+20"
It's always found 3 times and all 3 lines are in error

AHT bug fix. (I will upload and notify)
1. "strcpy( s2+20 , s2 );" should be "strncpy( s2+20 , s2 ,20);. // patched"
2. "strcpy( s3+20 , s3 );" should be "strncpy( s3+20 , s3 ,20);. // patched"
3. "strcpy( s4+20 , s4 );" should be "strncpy( s4+20 , s4 ,20);. // patched"

Now instead of crashing when any "unsupported" DIMM is met, AHT runs and then profile reports that particular DIMM is "unsupported". Finally, it turns out Every AHT 1.2.6-2.1 reports my G4's 3GB RAM correctly (in red color text).

And oh yeah, when I mentioned above that internet has always said AHT v1.2.6 was good for the MDD2003 model, I forgot to emphasize how horribly wrong they are. They've been doing it because they keep playing out the false narrative that MDD2003 is identical to MDD2002 and AHT v1.2.6 is what shipped with MDD2002. MDD2003 came with AHT v2.0.2 and on MDD2003 AHT v2.1 is even better.