[wei]

Was looking at the CPU upgrade for my 100Mhz bus speed PM G4. These is what I'm looking at:

-PPC 7455 1.4GHz with 2MB L3 cache
-PPC 7447 1.6GHz with 512Kb L2 cache (no L3)

Both priced the same. I wonder which will give me better performace? Will be using the mac to run Adobe CS, Macromedia studio other DTP task.

the G4 also have:
-1.25GB or RAM
-nVidia FX5200 128MB graphic card

thanks in advance!

[mduell]

I'd go with the 7447. The L3 seems too small and slow to matter.

[Lateralus]

7455, hands down.

Originally Posted by mduell

I'd go with the 7447. The L3 seems too small and slow to matter.

Might wanna brush up on how important cache is to the G4.

[bartman00]

mduell: are you on drugs? 2mb of L2 cache seems to small? What are you used to seeing? 2mb per cpu is as much l2 cache as any G4 has ever shipped with! The 7455 should be much faster. There where some good benchmarks flying around this forum with the 7447's hit.

[Eug Wanker]

The 1.4 GHz 7455 is slower than the 1.6 GHz 7447A. No wait, it's faster.

[mduell]

Originally Posted by Lateralus

Might wanna brush up on how important cache is to the G4.

While I didn't wade through all 10 pages of that thread, the barefeats article that thread links to says "The newest PowerBooks don't seem to suffer from the missing level 3 cache."

Originally Posted by bartman00

mduell: are you on drugs? 2mb of L2 cache seems to small? What are you used to seeing? 2mb per cpu is as much l2 cache as any G4 has ever shipped with! The 7455 should be much faster. There where some good benchmarks flying around this forum with the 7447's hit.

No, it's L3 not L2 that I was talking about. G4s have never shipped with 2MB on-die L2 cache (the first few revisions had 2MB off-die [read: slow] L2 cache). Off-die (slow) L3 cache can be meaningful if you can have enough to matter; 2MB isn't. Even 2MB on-die L2 is common these days on a $500 CPU.

Originally Posted by Eug Wanker

The 1.4 GHz 7455 is slower than the 1.6 GHz 7447A. No wait, it's faster.

Sure it is, if you're going to tie the 1.6's hands with a 100Mhz FSB.

[Eug Wanker]

Originally Posted by mduell

Sure it is, if you're going to tie the 1.6's hands with a 100Mhz FSB.

Well, isn't that the point? The original poster's machine is a 100 MHz FSB machine.

Anyways, I was originally gonna say just get the cheaper of the two, but they're both the same price. Given that, I'd go for the company with the better reputation.

[wei]

thanks guys~! it's really helpful.
well this is making my choice even more difficult...
so should I get the newer 7447A or the older 7455?
what if i take the 7447A at 1.7Ghz?

I've done some reading and it shows that the 2MB L3 cache do help on slower FSB machine like mine. But given 7455 1.4Ghz vs 7447 1.7/1.6Ghz is that a very big difference?

[Weezer]

gigadesigns is having a sale on the single 1.8 7447 for $300, which leads me to think the 7448 upgrades are in the pipeline...

[Eug Wanker]

Who makes the 7455 1.4 and 7447 1.7? If Sonnet makes one, but not the other, I would consider going with the Sonnet. Sonnet has the best reputation for reliability and customer support from what I've seen, although YMMV.

[Lateralus]

Originally Posted by Eug Wanker

Who makes the 7455 1.4 and 7447 1.7? If Sonnet makes one, but not the other, I would consider going with the Sonnet. Sonnet has the best reputation for reliability and customer support from what I've seen, although YMMV.

It's a little biased to proclaim that one company has the best support when you have only owned their products.

I've been through more PowerLogix, FastMac, Sonnet and GigaDesigns upgrades in the past few years for various machines than I can count. And while Sonnet's support may be good, I find Giga's to be better. And in the dealings I've had with PowerLogix since OWC took over support for them, I couldn't be happier.

It's all relative.

That said, assuming support and product quality are equal across the board, the best things to look at when picking out a product are price and versatility. Sonnet loses out on both. They're an established and reputable name, and they charge more for that. As for versatility, there isn't any with Sonnet's products.

[Eug Wanker]

Originally Posted by Lateralus

It's a little biased to proclaim that one company has the best support when you have only owned their products.

I've been through more PowerLogix, FastMac, Sonnet and GigaDesigns upgrades in the past few years for various machines than I can count. And while Sonnet's support may be good, I find Giga's to be better. And in the dealings I've had with PowerLogix since OWC took over support for them, I couldn't be happier.

It's all relative.

That said, assuming support and product quality are equal across the board, the best things to look at when picking out a product are price and versatility. Sonnet loses out on both. They're an established and reputable name, and they charge more for that. As for versatility, there isn't any with Sonnet's products.

I said support and reliability. I'm just going by what I have read on the Cube Owner's forum. The Gigas had a nasty habit of not working as advertised, at least in Cubes. Sure, they'd replace the item if necessary, but that sure doesn't bode well for their testing practices.

ie. Giga advertised a fanless 1.3. Guess what? It worked at 1.3... with a fan, but often didn't reliably work without one. Sonnet didn't sell a fanless 1.3 at all, but their products just worked at the advertised speed (with a fan). And so what if you couldn't overclock it? The same Cube-owning Giga buyers were underclocking their CPUs just to make them work right.

In the end the products may be similar in actual overall function, but I would prefer to deal with the company who provides the more honest assessment of their products.

As for PowerLogix, I'm glad that OWC has propped them up, but the horror stories we've all heard about them... It will take me a while to consider anything from them, even with OWC's backing.

[Cadaver]

My vote is for the 7455 w/ the L3 cache. The L3 cache really helps on machines with slower buses & PC100 RAM. Machines with fast buses (like the late model G4s and current PowerBooks with 167MHz buses and more modern RAM) seem to do fine with the higher-clocked cacheless models

I have a PPC7455B 1.4GHz (w/ 2MB L3) OWC Mercury in a Gigabit Ethernet G4 (originally a dual 500MHz machine) which has a 100MHz bus. The machine runs quite nicely*. Add a fast HD and enough RAM to give your apps plenty of room to breathe, and it should hold you a while.


*The only thing this machine could maybe use now is a CoreImage-capable card. It has a Radeon 8500 in it - did just peachy with MacOS X 10.3, but doesn't benefit from CoreImage effects with 10.4 (though over a 2x AGP bus, not sure it would really make that much of a difference). I do have an unused PC Radeon 9800 Pro that one day I'll flash to run on the Mac.

[Eug Wanker]

The only thing this machine could maybe use now is a CoreImage-capable card. It has a Radeon 8500 in it - did just peachy with MacOS X 10.3, but doesn't benefit from CoreImage effects with 10.4 (though over a 2x AGP bus, not sure it would really make that much of a difference). I do have an unused PC Radeon 9800 Pro that one day I'll flash to run on the Mac.

What are you doing with your 1.4 GHz that requires Core Image? Just wondering.

P.S. To my surprise, Aperture runs on my 1.7 GHz 7447A with GeForce 2 MX (Cube with 100 MHz bus). It's slow, but it works.

That's so far the only thing I use that really benefits from hardware Core Image support. I can do without the Dashboard ripple effect. I wonder how much iLife '06 will use Core Image though. (BTW, I was just testing this machine with Aperture... I'd actually be using this app on an iMac G5.)

[wei]

ahh... thanks again guys...
my final order is Gigadesign 1.8Ghz 7447A. $299, a good bargain huh?

i hope i made a right choice.

[Cadaver]

Originally Posted by Eug Wanker

What are you doing with your 1.4 GHz that requires Core Image? Just wondering.

Nothing. That's why I haven't bothered up to this point.

[bartman00]

Ment to say L3.. I have a Sawtooth I upgraded to a GIGA 1.0ghz overclocked to 1.3ghz with 2mb L3.. so excause me..

Originally Posted by mduell
Sure it is, if you're going to tie the 1.6's hands with a 100Mhz FSB.

Well that is what we're talking about..... a 100mhz FSB...