G4 Mystic Processor Upgrade

Hi-

I wouldn't worry so much about power..........

The best performing processor upgrade will be the dual 1.4ghz by Fastmac. The dual 7455 processors, each with 2mb L3 cache will give you outstanding performance. The dual 1.4 will out perform the dual 1.8ghz 7447 processor upgrade in all areas, with a hands down win in the graphics department. Dual processors with the L3 cache make all the difference.

There are only ancedotal comparisons (benchmarks?) of the 7448 processors. Based on my reading, I can't see that the 7448 would outperform, or if so, by much, the dual 7455. Especially for almost twice the price, for the dual 1.8 7448 loses out to the dual 1.4 7455 (IMHO).

The single 2.0ghz Powerlogix that I have, is a stellar performer. The only thing that kept me from buying a dual (almost 3 years ago) was lack of confirmation of the Uni-n 7 of my machine. The confirmation came, after installing the CPU Director software. WOW! I coulda had a dual.......Given the chance, I would install the dual 1.4 in my Sawtooth, no second thoughts.

http://store.fastmac.com/productinfo.php?productsid=198

G4AGP(450)Sawtooth, 2ghz PowerLogix, 2gbRAM, 300gbSATA+160gbATA, ATI Radeon 9800 Mac OS X (10.4.8) Pioneer DVR-109, ExtHD 160gb x2, 23"Cinema Display, Ratoc USB2.0, Nikon Coolscan

I can't speak for all applications- as you say, many don't place the demands on the duals. Photoshop rendering, 3D modeling, CAD, video rendering, game graphics- these all benefit from the dual processor. What you are saying was especially true in OS 9, and earlier versions of software, prior to the prevalence of dual processors. Now, OS X, as well as most third party software, have dual processor optimization built in. So much so, it's not advertised as it used to be. Also, with everything becoming more and more graphics intensive, the duals, combined with a performance graphics card, would really shine, as compared to a single.

Granted, not all gains are 40-60%, some are, some are 15-25%. But, a gain, is a gain.

I also have a Dual 450mhz GE (Mystic). It is only slightly upgraded- RAM, Graphics card, hard drive, superdrive, BUT, it loads the OS X, on start up, about 40% faster than this single 2.0. Not sure, but I would say that says something for the dual with L3 cache.

All things equal, if I did it again, I'd spend a little more money, for a lot more performance.

G4AGP(450)Sawtooth, 2ghz PowerLogix, 2gbRAM, 300gbSATA+160gbATA, ATI Radeon 9800 Mac OS X (10.4.8) Pioneer DVR-109, ExtHD 160gb x2, 23"Cinema Display, Ratoc USB2.0, Nikon Coolscan

Just to add that GigaDesigns are currently shipping a very similar CPU upgrade:

http://www.gigadesigns.com/
http://www.gigadesigns.com/index.asp?PageAction=VIEWPROD&ProdID=37

Many programs don't even take advantage of the dual processor setup.

If you haven't already done so, I guess you could always try using the Activity Monitor application included with OS X to see whether your existing applications do. OS X and the majority of applications these days seem to be multi-threaded to some degree and able to take advantage of dual processors. I suspect this will improve further still in the future with the release of Leopard and newer applications, especially now that multi processor and/or multi core machines have become the norm. Even if you are running a single threaded application such as a certain game, the chances are you'll also be running other applications at the same time (and the OS of course), so dual processors will still be of some benefit. I switched from a single to a dual processor and was pretty impressed by how well (and often) OS X was able to keep the load evenly split between each.

I'm also considering a processor upgrade for my 500Mhz. dual gigabit ethernet. Originally my idea was to get a dual 1.6Ghz. from Sonnet...but these are L2 cache. So now I'm reading about this L2 v. L3 debate about which one is faster so I'm intrigued by this. The Powerlogix is 256K 1:1 L2 Cache (on Chip), 2 MB SDR L3 Cache....but what does that mean exactly?
...Oh and what is a "Mystic" and what is 'overclocking" btw?

I'm good at soldering, I just repaired my Roland D-50 that had a key not working due to a link broken on the contact board...did a nice job IMHO..but no, I wouldn't mess around on my G4s' motherboard.

So now I'm reading about this L2 v. L3 debate about which one is faster so I'm intrigued by this. The Powerlogix is 256K 1:1 L2 Cache (on Chip), 2 MB SDR L3 Cache....but what does that mean exactly?

The caches are relatively small high speed memories that sit on the processor side of the system bus, to help offset it's relatively slow speed (100 - 167MHz) and high latency. Rather than having to fetch data and instructions from the main RAM via the system bus, they can be fetched from one of the caches instead. This works because the same instructions are often repeated several times in a row, for example if a Repeat Until or While Do loop is used, so there's a good chance the instructions will already be in the cache from when they were last fetched from the main RAM and executed.

The level 1 cache is in the CPU core itself and is the smallest (32K for data, 32K for instructions?) but also the fastest.

The level 2 cache is external to the CPU core but still on the CPU die. It's larger but may also be slower. '256K 1:1 L2 Cache (on Chip)' means it's 256K in size, runs at the same speed as the processor (hence 1 to 1 and in this case not slower) and resides on the CPU die or chip.

The level 3 cache is external to the CPU entirely and sits on the CPU daughter card. You can see the memory chip(s) if you remove the heat sink. It's the largest but also the slowest. '2 MB SDR L3 Cache' means it's 2 MB in size and uses single data rate RAM. 2MB is the largest the 7455 G4 processors can support (2MB per processor with dual processors). On my G4 (1GHz) I think they run at 4:1 or one quarter of the processor speed (250MHz). It may sound slow, but it's still faster than the 133MHz system bus and the latency is considerably lower.

Level 3 caches are particularly beneficial with G4 processors as the fastest system bus supported is 167MHz. With G5 processors, which have a faster system bus anyway, they're not used. Often a 1.4GHz 7455 G4 with 2MB level 3 cache will be comparable to a 1.8GHz 7447 G4 (which doesn't support any level 3 cache) in real world performance. I think the level 2 cache with the 7447s is twice the size (512K rather than 256K), but they lack the level 3 entirely.

Hummmm. Well that about sums it up in non-laymans' terms. Thanks a lot for that, Rodney. But does it mean that a 1.4 with L3 is faster than a 1.8 with L2?

Unfortunately there's no hard and fast answer, as some applications benefit from level 3 cache more than others. PhotoShop and certain games seem to benefit the most. In general I wouldn't say the 1.4 would be faster, but it could be just as fast. As well as clocking higher, 7447s also use less power and generate less heat, which I guess is partly why Apple used them in their laptops. This can be another consideration, especially with a dual processor upgrade in an early G4 which has a lower wattage power supply and limited ventilation. If it were me though, I'd go with the dual 1.4GHz.

....well so far, I'm leaning toward the 1.4 as opposed to the 1.6. I just got off the phone with Gigadesigns(who make the same processor for Powerlogix, btw) and they're saying that the L3 cache will work best for audio/video/photo app. users and will beat out at least a 1.6 L2 in a big way, increasing audio track count, amount of plugins per session and increasing rendering power. I'm using Pro Tools and sysnthesizers that use a lot of CPU so that sounds good to me.

It sounds as if it's better suited for the applications you're using. It's sad to think that Apple were shipping dual 1.42 GHz 7455s back at the beginning of 2003 though, almost half a decade ago, and they're still competitive today as far as G4s go.