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Review: XLR8's MAChCarrierTM G4/450
By Mike Breeden
|Benchmark tests were run with MacBench 5.0 as it is the accepted Mac standard. I've also included results of memory bandwidth tests using Newer Tech's free GaugePro utility and ATTO Tools' disk benchmark.
The MAChCarrier G4/450 ships set to a 50MHz bus speed and 9x Bus/CPU ratio and I ran all tests with a 225MHz backside cache speed (controlled via software). I never touched the card's settings for this review. The S900's motherboard cache (512KB) was disabled unless otherwise noted, and the backside cache was set to copy-back (faster) mode. (See the Software Controls page of the review for info on how cache speeds/modes are set.)
Remember that Macbench Graphics scores will vary depending on resolution, color depth and the installed video card. This is not a reflection on the CPU card under review. Ditto for disk scores, as the hard drive type, speed and free space/fragmentation all affect scores. The baseline 1000 score is based on the results with a Beige G3/300/150/1MB (with extensions on of course).
Although I cannot recommend overclocking to others due to the risks involved, I did try the G4/450 ZIF module in a B&W G3 to see if it would run at 500MHz. Although it booted, there were errors running applications. This sample, at least without voltage tweaks, would not run reliably at 500MHz for those that are curious. Never buy a CPU upgrade assuming it will run overclocked. Each CPU chip, system/ram/cache/motherboard combination is somewhat unique and results can vary. Never assume someone else's results will be reliable or repeatable in your system.
MacBench 5.0 Tests: The graphs below compare the follow configurations and systems
All systems were run with as similar an extension set as possible.
The first graph shows the results of the S900 before and after the G4/450 upgrade
MacBench 5.0 Performance - S900 604e/200 vs S900 w/XLR8 G4/450 Upgrade
How the S900 w/450MHz G4 Upgrade Compares to More Modern Macs
Notes: Some explanation of the MacBench graph and test components.
I didn't include G4timedemo results in the S900 due to the fact the benchmark would not run with the Voodoo3 card installed (I did not install the Voodoo2 RAVE extension, which may have helped). Consider the scores below for reference only -- to illustrate the benefit of the G4's Velocity Engine/Altivec with software that supports it.
The graph shows performance from an XLR8 G4 ZIF upgrade in a B&W G3 (overclocked to 450MHz) compared to the same system with a G3/400 CPU and also a G4/450 AGP Mac. Note the improvement a G4 makes over a G3 in this benchmark which takes advantage of Altivec/Velocity Engine instructions.
ATTO Tools Disk Benchmark Results:
I used ATTO's Tools benchmark since it tests the drive and interface, and doesn't use the OS's disk cache by default. I discovered some very interesting results during testing of hard drive performance between the 604e/200 and the G4/450 in the S900. FYI: These tests were done after updating the S900 to OS 9.04 and adding an XLR8 PCI USB card (w/USB drivers v1.4.1).
What I discovered (repeatable) was with the G4 CPU upgrade installed, if the S900's 512K motherboard cache was enabled read *peak* rates were dramatically lower - almost 1/3 lower as shown in the graphs below. I repeated these tests 3 times (rebooting clean before each test as I do in all cases). Note: I do no recommend running with the motherboard cache enabled. As noted in all the site's troubleshooting guides, remove or disable the original L2 cache when installing a G3/G4 upgrade card is usually recommended or required for stability.
Also note that with the Acard IDE controller/Maxtor drive, a 604e/200MHz CPU delivers nearly the same pure disk performance in this benchmark as the 450MHz G4 CPU (250MHz faster CPU).
Now look at the peak read rates with the motherboard cache enabled:
Now the results with the same system, but a 200MHz 604e card
Memory Bandwidth Tests:
Although 100MHz bus speed Macs have generally 100MB/sec or higher memory performance, note that as shown on the Applications Tests page, the huge advantage in memory bandwidth is often not a factor in many applications tests. The efficiency of the L1/L2 caches isolate the system bus speed in most cases to where it is often not a factor in real world application performance. For this review I've limited bandwidth tests to just GaugePro (past reviews often used Stream and another memory benchmark).
Newer Tech's Gauge Pro 1.01 Results:
The GaugePro results below are from the exact same S900 configuration except for the CPU card as noted in the images. Both upgrades run at the same bus speed.
Now the same test with the XLR8 G4/450 CPU card installed:
Reported memory bandwidth was almost double with the 250MHz faster G4 CPU. BTW - a 604e CPU card running at 211MHz and 60.3MHz bus speed reported appx. 38MB/sec rates. I had previous set the PowerBoost Pro 604e card to 60.3MHz bus speed for tests in a PowerCenter Pro some time back and was impressed it even booted at that speed in the S900. I did not run any apps other than GaugePro due to time constraints, so I can't say if that bus speed would have been reliable in long term use. Still impressive for an onboard cache motherboard with interleaved RAM.
FYI: As noted in past G4 ZIF upgrade reviews, my G4/450 AGP (Sawtooth) system reported just over 115MB/sec using a beta version of GuagePro. The v2.6 G4 in the Sawtooth has errata (L1 cache wait states I'm told), so current G4s may have higher results.
|Summary: In other than memory bandwidth tests, benchmark performance of G4 upgrades are as good or better than my G4/450 (v2.6 CPU) Sawtooth system in most cases. Benchmark performance is interesting for technical reasons, however I prefer to rely on real world application performance since that's what really counts. Application and 3D Game tests are covered in the next page of this review. Or you may use the links below to jump to a specific page.|
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