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SHOOTOUT:
Dual Core 2.0GHz
versus Single Core 2.0GHz Power Mac

Originally posted October 31st, 2005, by rob-ART morgan, mad scientist

We've received many questions regarding the new Dual-Core G5 Power Macs. One of the questions asked most often is, "Assuming both are running at the same clock speed, will a dual single-core G5 Power Mac go faster than a single dual-core G5 Power Mac?" Last week we got our hands on a Dual-Core G5/2.0GHz Power Mac to compare to our dual Single-Core G5/2.0GHz Power Mac. So without further ado, here are our findings...

GRAPH LEGEND: Single Core = Dual Single-Core G5/2.0GHz Power Mac
Dual Core = Single Dual-Core G5/2.0GHz Power Mac
66LE = GeForce 6600LE PCI Express Graphics Card
96XT = Radeon 9600 XT (OEM) AGP 8X Graphics Card
98SE = Radeon 9800 Pro Mac Special Edition AGP 8X Graphic Card

ANALYSIS
On strictly CPU intensive tasks (top three graphs), the single Dual-Core G5/2.0GHz Power Mac was as fast or faster than the dual Single-Core G5/2.0GHz Power Mac. The 1MB L2 cache in each of the Dual-Core's processors doesn't hurt. However, with the trend toward utilizing the graphics processor to help with rendering, you have to take the graphics card into consideration in the Motion and iMaginator graphs.

The Dual-Core with the GeForce 6600LE and the Single-Core with the Radeon 9600 XT represent typical configurations for those two platforms. The Dual-Core easily beat the Single-Core until we added the 9800 Pro SE.

When it comes to OpenGL 3D accelerated games, the Dual-Core beat the Single-Core two out of three -- until we added the Radeon 9800 Pro SE to the Single-Core. It's a tough call as to which graphics card is most fair in the comparison since we can't really run identical cards on both systems. FYI, here are the specs on the cards we used in this particular test session:

Radeon 9600XT
GeForce 6600 LE
Radeon 9800 Pro SE
Core Clock Speed
402MHz*
425MHz
378MHz
Memory Clock (DDR)
622MHz
1000MHz
675MHz
Pixel Pipelines
4
4
8
Vertex Shader Engines
2
3
4
Frame Buffer Memory
128MB
128MB
256MB
Pixel Fill Rate
1.6GB/s
1.2GB/s
3.0GB/s

(* Though the 9600 XT should be running at 500MHz, Apple clocked theirs at 400MHz, making it a 9600 Pro in reality.)

Don't forget to see our comparison of the Quad-Core G5/2.5 Power Mac with the Single-Core Dual G5/2.5 Power Mac.

BEST BUY?
If you are upgrading from a G4 Power Mac and you are trying to decide between a "close-out" or refurbished Single Core and a new Dual-Core (both running at the same clock speed), you aren't giving up any performance to choose the Dual-Core. But you could save some money going with the Single-Core -- and have enough left over for a better graphics card.

If you are trying to decide whether to sell your Single-Core G5 Power Mac to buy a Dual-Core, I don't think it makes a lot of sense -- especially if you have a large investment in PCI-X adapters and memory. On the other hand, if you are considering replacing your Single-Core G5 with a Quad-Core G5/2.5GHz that's a whole different story. We expect our testing to show it to be a screamer, especially when running multi-processor aware applications like Photoshop (Certain Filters), Final Cut Pro (Render Effects, Export), QuickTime (Export), iMovie (Render Effects), After Effects (Render) and Cinema 4D (Ray Tracing).

SHOULD I BUY CAS 4 OR CAS 3 MEMORY FOR THE DUAL-CORE?
We ran some memory tests using Xbench and MemPerf with both factory CAS 4 and third party CAS 3 memory (PQI Turbo). The most dramatic difference was seen in the fill rate test where the CAS 3 was 9% faster. Compared to the 400MHz memory in the Single-Core G5, the 533MHz memory in the Dual-Core had a fill rate of 82% faster. (See graph below.)

Other memory tests weren't as dramatic. The average on the STREAM test showed the CAS 3 memory to only be 3% faster. More to the point, when we ran our real world tests, the times were virtually identical no matter what memory we used.

QUIET
We were impressed with quietness of the Dual-Core system. All during testing it never exceeded 42 decibels. The Single-Core system idled at 48 decibels and would climb over 53 when while CPU intensive tests were run. (Our Single-Core G5/2.5GHz Power Mac goes over 60 decibels when "busy.") We noticed that the fan enclosure in front of the CPUs has been modified on the Dual-Core. Maybe it works more efficiently than the old fixture and/or Apple tweaked the fan management software.

PCI EXPRESS BAY STILL NOT "FIXED"
Those of you who have Blackmagic Design DeckLink HD capture cards might remember how you have to bend and torque the card to get it into slot 4. The power connector for the CPU rear cooling fans is in the way. It also prevented us from installing the Sonnet Tempo-X eSATA 8 in slot 4 of the Single-Core. I was hoping that the offending connector had been moved. Nope. Still in the way. (Sigh)

HAS THE FIREWIRE 800 WRITE SPEED IMPROVED?
No.
We hooked up our dual G-RAID four drive FireWire 800 array to the built-in port on the new Dual-Core as well as the old Single-Core and our G4/1.5GHz PowerBook. As you can see from the graph below, the PowerBook blows both of them away. The write speed issue has NOT been addressed. It's crazy.

RELATED ARTICLES
Quad-Core G5/2.5 Power Mac versus Single-Core Dual G5/2.5 -- G5/2.7 results included in Photoshop CS 2 and After Effects tests. A special 3D GAME page added which includes results for the GeForce 7800 GT and Quadro FX 4500.

WHERE TO ORDER YOUR DUAL-CORE G5 POWER MAC

When ordering products from Apple Store USA, please click THIS TEXT LINK or any Apple display ad as your "portal" to the online store. In so doing, you help to support Bare Feats. (DON'T LIVE in the USA? See links for Apple online stores in other countries.)

The best deal on memory for the Dual-Core and Quad-Core is at Other World Computing. They are one of the few companies shipping a 4GB (2GBx2) kit and at a radically low price. Check out their PC2-4200 memory page!

For refurbished, reconditioned, open box (as well as new) G5 Power Macs, check with Small Dog and Power Max. Check also at the Apple SPECIAL DEALS section for factory refurbs and other specials.

Some of you have asked which "older" G5 Power Mac models are most desirable. I recommend getting a model with 8 memory slots, 100/133MHz PCI-X slots, and 600W Power Supply. The table below gives the model number, etc., of these most desirable older G5s.

Model Number
clock speed
processors
intro date
M9031LL/A
1.8GHz
single
June 2003
M9032LL/A
2.0GHz
dual
June 2003
M9393LL/A
1.8GHz
dual
November 2003
M9455LL/A
2.0GHz
dual
June 2004
M9457LL/A
2.5GHz
dual
June 2004
M9748LL/A
2.3GHz
dual
April 2005
M9749LL/A
2.7GHz
dual
April 2005

All other previous models have only 4 memory slots, 33MHz PCI slots, 450W Power Supply, and slower frontside bus speeds. If you can't find the model you want at Apple's Special Deals page, Small Dog's site, or Power Max's site, go to Froogle.com and search on the model number.

PCI EXPRESS HOST ADAPTERS

SATA II -- HighPoint Technologies has posted Mac drivers for their RocketRAID 2320 PCI Express 4X SATA II RAID host adapter (8 internal ports, RAID 0, 1, and 5 support). I'm sure all the "usual suspects" will have PCI Express host adapters available soon. Hopefully at least one of them will have external ports with port multiplication.

FIREWIRE 800 -- We've been contacted by a company who has a PCI Express FireWire 800 card that runs on Macs and PCs. We'll report on that shortly.

SCSI -- Atto Technology announced an Ultra 320 SCSI PCI Express card (UL5D).

Serial Attached SCSI -- Adaptec has a PCI Express version of their Serial Attached SCSI host adapter. I've heard they are planning a Mac verson, but Mac OS X is not listed as one of the supported Operating Systems.

FIBRE CHANNEL -- Apple has posted a link to their PCI Express version of their Fibre Channel card. I expect ATTO's new 4-Gigabit Fibre Channel PCI Express card to be offered in a Mac version.

VIDEO CAPTURE -- Blackmagic Design's "World's First PCI Express Capture Card" is now officially compatible with the Dual-Core and Quad-Core G5 Power Macs. AJA has a PCI Express version of their Kona card called the LHe.

AUDIO PRODUCTION -- Digidesign is working on a PCI Express version of Pro Tools HD scheduled to ship before the end of the year.

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2005 Rob Art Morgan
"BARE facts on Macintosh speed FEATS"
Email , the webmaster and mad scientist