Dual 7448 for MDD

[theos911]

Is there such a thing? I was looking at Newertech's options, but they don't list the MDD as compatible with their Dual 1.8GHz 7448 . Would it work in a MDD or are there other options?

http://www.newertech.com/products/maxpower48.php

http://www.barefeats.com/g4up2.html

 

[ClassicHasClass]

It's not the chip, it's the board; MDDs are a completely different design.

 

[theos911]

Ah, ok then, two different cpu boards. I see now.

Though, could anyone point me in the direction of a dual 7448 that is MDD compatible?

 

[ClassicHasClass]

I have never seen a 7448 upgrade for the MDD. Like I say, it's just because one was never made. My Sonnet Encore/MDX card has 7447As on it, and other than the Giga Design dual 1.33GHz 7455 (which despite its clock speed is also a fairly compelling upgrade), I'm pretty sure that's all the MDD upgrade cards that exist.

 

[theos911]

Would the higher clocked Dual 7448's outperform the lower clocked 7447a(s) and 7455(s) when used on the QS's slower 133 Bus?

 

[ClassicHasClass]

Probably, because the 7448 has double the L2 of the 7447. The Giga also has L3 cache, if I remember correctly, which the 744x series lack.

 

[johnklos]

I asked what people guessed about this very thing:

http://68kmla.org/forums/viewtopic.php?f=13&t=16764

The two test systems were:

System one: 1.8 GHz 7447a in a MDD tower with 2 gigs of DDR memory

System two: 1.733 GHz 7448 in a digital audio tower with 1.5 gigs of 133 MHz SDR memory

Small CPU benchmarks showed that the faster clock rate was obviously faster so long as everything fit into the cache, but larger benchmarks and tasks showed that the larger L2 cache in the 7448 more than made up for both the slower clock speed and the slower memory bus. In many instances, the 7448 system was more than 10% faster than the 7447a system doing stuff in BSD.

 

[theos911]

Thanks, that situation is a bit different, but very helpful.

Here we would have:

MDD: Single 1.8 GHz 7447a 167 Bus

QS '02: Dual 1.8 GHz 7448 133 Bus

Your (johnklos) results show that for data intensive things, the QS would beat out the MDD. This would be even furthered by the dual cpus. Would the smaller benchmarks do any better with the dual cpus?

Would the NewerTech upgrade have 1MB cache shared by both CPUs, 1 MB for independent for each, or 2MB that they can both access? Obviously, no L3 cache.

*Quasi-relevant: http://forums.macnn.com/65/mac-desktops/356348/dual-7447a-or-single-7448-a/

Summary: Same Bus, Slower Dual 7447a faster for most things than Faster Single 7448.

Notes:

Leopard runs a lot better on dual cpus. The 7448 is a good bit cooler and draws less power.

 

[johnklos]

Here we would have:MDD: Single 1.8 GHz 7447a 167 Bus

QS '02: Dual 1.8 GHz 7448 133 Bus

Your (johnklos) results show that for data intensive things, the QS would beat out the MDD. This would be even furthered by the dual cpus. Would the smaller benchmarks do any better with the dual cpus?

Only multithreaded benchmarks.

Would the NewerTech upgrade have 1MB cache shared by both CPUs, 1 MB for independent for each, or 2MB that they can both access? Obviously, no L3 cache.

It's 1 meg of CPU speed L2 which is physically built-in to each CPU, so it's not shared.

*Quasi-relevant: http://forums.macnn.com/65/mac-desktops/356348/dual-7447a-or-single-7448-a/Summary: Same Bus, Slower Dual 7447a faster for most things than Faster Single 7448.

Notes:

Leopard runs a lot better on dual cpus. The 7448 is a good bit cooler and draws less power.

Yes, Unix in general and OS X in particular will always be better off with more than one CPU. Mac OS 9 couldn't care less.

 

[Tron]

In my opinion, almost all G4 do it very well in everyday task. When I make a speed comparison between some of my "high end" G4 machines I like to do it centered in video playback and encoding, because even this can be considered a common task, it compromise all the machine architecture, from hard disk to CPU, passing to all buses, memory an caches and also because even today (2012) cpus fall in some way in this task.

I have tested my 7448@2Ghz in a sawtoth at 120Mhz and 133Mhz bus, but even it was a little fast in a lot of task than my MDD 7455@1.5Ghz it falls in video encoding and other hard task (whithout talking of the superiority of my winter time only dual 7455@1.66Mhz

Now I understand why a 7448 never whas done. Because never whas really needed: in a 166Mhz DDR bus the 512k of L2 in the 7447 are mainly enougth. Further more, any body, any where has saw a 7448 as dual CPU in os 9? but 7447 may work as dual, if the card has 2 CPU of course

Sorry for my bad English.

 

[theos911]

I guess the MDD got the short end of the stick on upgrades. The QS is where its at.

So, if I've got this right:

Fastest 7448:

Newertech 1.7GHz Dual

Newertech 2.0GHz Single

Fastest 7447:

Giga Designs 1.8GHz Dual

Giga Designs 1.8GHz Single

All 4 not compatible with the MDD.

 

[Unknown_K]

Yea, you are pretty much stuck with OEM CPU upgrades or super expensive hard to find 3rd party ones for the MDD. The QS and other AGP G4's have a wide variety of upgrades (I have a 1.25 Ghz single G4 in one of my QS's made bu Sonnet). The layout for the CPU is different on the MDD and I guess the market for high end G4 upgrades died when the G5 came out or 3rd parties had a hard time getting faster G4 CPUs since Apple had first pick for Powerbooks?

 

[ClassicHasClass]

The Sonnet Encore/MDX is also a dual-CPU 1.8GHz design (I have dual 1.8s in my MDD). The cores are 7447A.

 

[Bunsen]

Those upgrades are available, at time of this posting, much cheaper through OWC.

They also appear to be the last and only new G4 upgrades still on the market, unless anyone has another lead.

 

[theos911]

Sonnet Encore/MDX Dual 7447A @1.8GHz

Ok, now I understand.

Both the QS & The MDD can get the top Dual 7447 (1.8GHz), albeit from different companies. At that point, the MDD simply wins due to faster bus speed.

The QS seems to have it in the bag for ultimate clock rate / fastest 7448 with its 2.0GHz SP, which I'm guessing between the bigger cache and extra 200Mhz easily makes up for the slower bus. (especially since the only MDD comparison drops to a 7447 @1.8 on a slightly faster bus.)

Here's an interesting one though:

1.8GHz Dual 7447A in 167 MDD vs 1.7GHz Dual 7448 in 133 QS? Faster Hz, Smaller cache, Faster bus vs. Slower Hz, Larger cache, Slower Bus, More efficent Core