Much performance difference between PCI and PCI-X?

[PhilBuckle]

I have the opportunity to buy a .......

Power Mac G5 Dual 2GHz (M9747LL/A) takes DDR3200 Memory (4 Slots, Holds up to 4GB of memory)
(its the only Dual 2Ghz G5 from Apple that has 4 slots)

It's a strange machine in that it is a 2005 third generation model but has PCI slots. Here is why....

Eight RAM slots before April 27, 2005, four RAM slots after.

AND

Before April 27, 2005, 3 full-length PCI-X slots: one 133 MHz, 64-bit
... slot & two 100 MHz, 64-bit slots, AirPort Extreme, & Bluetooth. After
... April 27, 2005, 3 full-length 64-bit, 33 MHz PCI slots, AirPort
... Extreme and Bluetooth (no PCI-X support).

I don't know why the NEWER machine reverted to PCI slots.

I don't mind about the 4 gig ram limit. That's fine with me.
What I'm concerned about is the PCI speed of 33MHz

So does this slow PCI speed make a huge difference?
Is this machine a "lemon"?
Or should I go ahead? The machine is supported by Digi.

I am running a HD Accel2 system in a Dual G4 867 at the moment.
Thanks.

[PhilBuckle]

Appreciate some feedback on this.

[bashville]

Hi--

I don't know about TDM performance per se, but I remember posts from the Fxpansion guy Angus that you could expect better performance streaming RTAS with the faster bus. He said there was a bottleneck with PCI that was alleviated with PCI-X, and it didn't have so much to do with raw CPU power as it did with bus speed.

I'm interested that Digi has said their Expansion chassis (which is PCI, not PCI-X) introduces some delay using RTAS. Magma is supposed to be coming out with a 66mHz chassis vs. Digi's 33, and I'm curious if that will be better for RTAS.

That 2 gig machine is PCI because the cheapest of whatever 3 speeds Apple was offering at the time was always PCI, not because they downgraded the 2 gig. They really upgraded the processor on the PCI machine. 1st it was 1.6, them 1.8, and finally 2. They always offered three speeds at a time. My 2 gig is PCI-X because the machines then offered were 2.5, 2.0, and 1.8.

Come to think of it, you better check Digi's system qualifications carefully, because they may not have ever supported the "bottom" machine once PCI-X came out.

Good luck--

Kevin

[PhilBuckle]

Thanks very much for that info. The seller also has an older Dual 2 gig machine with 8 ram slots so after checking all available models I am assuming that it is PCI-X.
In fact according to my sluething Apple never made a dual 2 gig 8 ram slot machine that was not PCI-X

That model had me really confused because it was newer and yet had PCI.
Thanks again.

[mixer]

Thanks very much for that info. The seller also has an older Dual 2 gig machine with 8 ram slots so after checking all available models I am assuming that it is PCI-X.
In fact according to my sluething Apple never made a dual 2 gig 8 ram slot machine that was not PCI-X

That model had me really confused because it was newer and yet had PCI.
Thanks again.

my pci dual 2 g5 has 8 slots and it's not pci-x

[PhilBuckle]

[/QUOTE]
my pci dual 2 g5 has 8 slots and it's not pci-x

[/QUOTE]

Your model doesn't appear on Everymac.com or on Mactracker.
Do you know what the actual model# is?
Very confusing!!

[Ed Kish]

I have a dual 2.7 that has 8 slots and is PCI

[francois]

Post deleted by francois

[PhilBuckle]

I have 2 dua PCI l with 8 slots one 2ghz and one 2.7ghz.
I just bought the later on apple.com .check the refurbished link.It's the second machine i buy like that and both time it came with 1 gig of ram instead of 512 announced.They might have a few 2.7 left.just be aware of the compatibility with HD3 in the comp section of DIGI.
I use a Magma chassis and needed the fastest PCI Mac G5 to last me thru the mehem of PCIe - MActel- plugins compatibility.
Francois

So it would seem that there are 8 slot models with either PCI or PCI-X slots. All sharing the same model number. Confusing.
If you look at Mactracker or the "Everymac" site you will see NO dual 2gig 8 slot machines listed with PCI slots!!

Only that strange Power Mac G5 Dual 2GHz (M9747LL/A) was released with 4 slots and PCI slots.

Either you guys are wrong....do you really know if you have PCI or PCI-X OR these sites don't bother to list your models.

To top it all off I've discovered that HD and Accel cards only run at 33MHz so even if you use PCI-X the bus will slow down for the slowest card.
What's the big advantage of PCI-X?

Maybe Rail knows?

[PhilBuckle]

Ok let me ask this in a different way.

Given that HD cards run at 33MHz is there any advantage to the faster bus speed of PCI-X slots as opposed to PCI slots.

The PCI-X bus slows to the clock of the slowest card installed and works at 33mhz.

My confusion is that I'm being told to only buy a machine with PCI-X slots simply because they are "faster"