Digital Audio G4 - overclock the bus speed?

[macuser453787]

Does anyone know if it's possible to overclock the bus speed on a Digital Audio? I've found places online where folks talk about overclocking other G4 models but haven't found anything specific to the DA.

If anyone knows, I would be interested in some concrete/proven step-by-step instructions. I've done just about everything else that can be done upgrade-wise to my machine, but some faster overall performance would be great.

BTW just want to say up front in case anyone wants to know if I've upgraded the GPU, the CPU (and overclocked it), put in SSD for boot drive and maxed out the RAM, the answer to all of those questions is yes.

 

[Intell]

The bus already runs at 133Mhz. There's really no way to make it run faster like on 100Mhz PowerMacs. Mostly because PC-166 ram doesn't exist.

 

[macuser453787]

The bus already runs at 133Mhz. There's really no way to make it run faster like on 100Mhz PowerMacs. Mostly because PC-166 ram doesn't exist.

Ah, good point. Thanks, I did not think about that. So just so I understand, even if it could be done, the fact that the RAM is PC133 could actually become a hindrance to the faster system bus since the RAM itself would then be running slower - right?

 

[MisterKeeks]

Ah, good point. Thanks, I did not think about that. So just so I understand, even if it could be done, the fact that the RAM is PC133 could actually become a hindrance to the faster system bus since the RAM itself would then be running slower - right?

Yeah, it would be pointless.

 

[Intell]

Ah, good point. Thanks, I did not think about that. So just so I understand, even if it could be done, the fact that the RAM is PC133 could actually become a hindrance to the faster system bus since the RAM itself would then be running slower - right?

Correct. The ram might overclock a bit, but not by much. Then overclocking the bus would also make the CPU go faster, so you'd have to change the multipliers to make it all even out.

 

[macuser453787]

Yeah, it would be pointless.

Correct. The ram might overclock a bit, but not by much. Then overclocking the bus would also make the CPU go faster, so you'd have to change the multipliers to make it all even out.

Okay folks thanks so much for the help! I will consider that a no go then.

Man would be nice to do something more for this machine though. I've thought about feasibility of other more research- and labor-intensive upgrades, such as the possibility of changing the RAM controller chip in an effort to get the machine to recognize 1gb RAM modules so that I could double the RAM to 3gb. (Yes, they exist for the type of RAM used by DA. And yes, I tried putting one in my machine as is and it didn't recognize it. Just had to know for myself.) But I don't even really know if just switching out the RAM controller chip would accomplish that in and of itself. And I don't know if it would be worth time and expense if it is even possible...

 

[Intell]

1GB PC-133 non-ECC ram doesn't exist, only in the ECC variant. That's where that problem is.

 

[macuser453787]

1GB PC-133 non-ECC ram doesn't exist, only in the ECC variant. That's where that problem is.

Well granted I had difficulty finding them, but evidently such modules do exist. I found them here:

http://www.memoryx.com/gn1.html

And here:

http://www.ebay.com/itm/1GB-168-pin...2438413?pt=US_Memory_RAM_&hash=item5ad6e5c28d

And here:

http://www.ebay.com/itm/1GB-SDRAM-M...8700986?pt=US_Memory_RAM_&hash=item4cf47323ba

And under other ebay listings that are expired.


So I bought a module directly from memoryx and it looked more like the one shown in the 2nd URL (the 1st ebay listing). Alas, it did not work. So I returned it to them for a full refund minus shipping cost.

After that I decided to just replace all three 512mb modules with the high-performance CL2 RAM from OWC. In case anyone has ever wondered if it makes a difference, I can definitely say I noticed a difference after installing it. Is the difference worth the price? Maybe not, but my machine was moving faster after the install. Not significantly faster, but faster.

 

[Intell]

I'm very sure no machine ever made can make use of that ram except for servers. That ram is either mislabeled ECC, actually 512MB but with a different registry table to make it look like 1GB, high density ram, or a scam. That ram is outside of the SDRAM specification for a reason.

 

[macuser453787]

I'm very sure no machine ever made can make use of that ram except for servers.

I think the one shown on their website seemed to have some pretty specific uses, though I definitely could be remembering wrong. However my desire to be able to have more RAM and the fact that I basically had nothing to lose by trying it (other than a few bucks for shipping) were really the deciding factors there.

That ram is either mislabeled ECC, actually 512MB but with a different registry table to make it look like 1GB, high density ram, or a scam. That ram is outside of the SDRAM specification for a reason.

Well if that was their general practice then I reckon they'd have some pretty dissatisfied customers and wouldn't be in business for long. We can probably rule out a scam since I did get my money refunded, without any hassle I might add. I'm not really knowledgeable enough on this subject so I could only trust what I was seeing at the time.

For my edification, why is it that you say those modules are outside of the SDRAM spec?

 

[Intell]

For my edification, why is it that you say those modules are outside of the SDRAM spec?

It is out of spec because Intell, the company that helped created the SRD SDRAM spec, never wrote out address bit maps for row and column addresses during commands for 1GB non-ECC sticks.

 

[macuser453787]

It is out of spec because Intell, the company that helped created the SRD SDRAM spec, never wrote out address bit maps for row and column addresses during commands for 1GB non-ECC sticks.

Interesting. I guess something is off about those listings then, as you said.