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  Review:OWC's Mercury G3 ZIFs 350MHz and 400MHz Models By Mike Published: 10/17/99 |
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| Introduction | |
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Later ZIF Reviews: For a review of the lower-priced OWC Mercury G4/500 vs. G4/400 vs. G3/500 CPU upgrades, see this Oct. 2001 review which includes OS 9 and OS X performance test comparisons, installation tips and guides. (Original 1999 written review comments follows.) Other World Computing has been selling OEM (original equipment manufacturer) ZIF CPU modules for some time for use in Apple G3 systems. When paired with the XLR8 CarrierZIF, you can also use the Mercury ZIFs in CPU Card slot Macs such as the 73-9600, and many clones (see below for a complete list). For more information on the CarrierZIF, see the CPU Cards page for a list of several CarrierZIF reviews and articles. If you're confused about ZIF upgrades with the CarrierZIF see my illustrated Setup Guide to the CarrierZIF for more information and important installation tips. I rated these upgrades a 4 out of 5 primarily due to their low cost/MHz. Currently they are much lower in price than most 'name brand' G3 upgrades of the same speed (often hundreds less). The savings could be used to a) add more RAM or b) add a better video card; therefore addressing two performance areas for the same price as a 'name brand' CPU upgrade alone. These Motorola ZIFs are reportedly being sold under other brand names and by other dealers as well. If you're not experienced with installing upgrades make sure you read all pages of this review, especially the installation page and list of recommended articles. Models Reviewed:
As of this review date (October 1999), prices are $209 for the 350MHz and $265 for the 400MHz model. Is an OEM ZIF a Good Fit for You? There are two main things to consider when buying an OEM Jumperless ZIF CPU Upgrade like these.
Note to owners of CPU Card Slot Macs: (Apple G3 owners can ignore this.) Most G3 CPU chips on the market now have a maximum Bus/CPU ratio of 8X. That means your Mac has to be able to run a 50MHz bus speed to allow a 400MHz CPU speed (50 x 8 = 400). This is only an issue with older Macs, as the 66MHz and 100MHz bus speeds of the Apple G3 systems don't have this limitation. In my experience with the CarrierZIF base card many Macs (with the L2 Cache dimm removed) can run 50MHz bus speeds fine, but only tests in your specific system setup can determine what is reliable with your combination of RAM and other system hardware. 10X Ratio G3 CPUs are now available but cost substantially more (often twice as much or more) as these Mercury models. If your Mac is bus speed challenged however, the 10X ratio CPUs may be worth the extra money. They will allow a CPU speed of 10 times your bus speed (depending on the rated speed of the CPU chip of course). For those that don't want to read all 7 pages of this review here is a summary of the pros and cons: Pros: Lowest cost/MHz G3 upgrades as of this date. Good value for those looking for 'bare-bones' upgrades. Current revision CarrierZIF cards allow using these ZIF CPU modules as cost-effective upgrades to older Macs. Cons: Sparce documentation may be a negative for inexperienced upgraders. Requires changing jumper settings on Apple G3 motherboards which voids Apple warranty. First model CarrierZIF cards may have issues with these OEM ZIFs in older Macs often requiring deinterleaving RAM or lowering bus speeds (XLR8 revised the design to address this issue). For other owner feedback on OWC Mercury ZIFs - search my Rate Your G3 Upgrade database. (Note: To find reports on OWC ZIFs, Beige/B&W G3 owners should select 'Other World Computing' as the card brand and their Mac model (Beige or B&W G3). Older Mac owners should select 'XLR8 CarrierZIF' as the card brand and look for OWC ZIF comments next to the CPU speed or in the comments since the CarrierZIF is required to use ZIF upgrades in older Macs.) Recommended Reading: For jumper settings and installation information see the installation page of this review. System Compatibility: The OWC Mercury ZIFs are compatible with the following Mac models:
Using the XLR8 CarrierZIF as a base card, you can use the Mercury ZIF with the following Mac models [based on CarrierZIF compatibility as of 9/99]:
* I recommend PowerTower Pro owners call XLR8 to check compatibility with their logic board. Although XLR8 has revised the CarrierZIF card design and this may be solved now, I still suggest verifying before you buy. My Results: I ran tests at both the rated speeds, and stress tests at the maximum reliable frequency (called overclocking or fmax testing) on both ZIFs. I do not recommend overclocking to others as it can affect reliability and could lead to data loss. OWC sells some ZIF models that are guaranteed to run at a certain speed over the rated value, contact them for details. Maximum reliable speeds will vary by individual CPU and system. I was surprised however to see that in the Genesis (via the CarrierZIF card), the 400MHz ZIF CPU would not run reliably at any significant speed over 400MHz (416MHz for instance showed random errors at boot after running for several hours). To prove that the bus speed was not the reason, I lowered the CPU/Bus ratio to reduce the CPU speed to prove that the bus speed was reliable - it was. Therefore it seemed in my loaded Genesis with the CarrierZIF at least, the 400MHz ZIF was not really overclockable. (Readers have reported different results with these same ZIFs however, so my experience may not be typical.) What was surprising was that the same ZIF ran reliably at 434MHz in my Beige G3 (it actually ran 466MHz for several hours but had an error during Macbench testing so I back down to the next lower speed). Perhaps the voltage in the Beige G3 was a bit higher or the heatsink was more efficient perhaps. Regardless this shows that your mileage will vary depending on system and the particular CPU. At least one other OWC Mercury 400 owner reported running 466MHz speeds in a Beige G3 for several weeks in a recent entry in my Rate Your G3 Upgrade database. Other Owner Experiences: Many owners of Other World Computing Mercury ZIFs have posted their ratings, speeds and commenst in my searchable Rate Your G3 Upgrade database. Apple G3 owners should select 'Other World Computing' as the card brand and either Beige or B&W G3 as the Mac model. To see Mercury ZIF reports when used in a CarrierZIF (in older Macs), select 'XLR8 CarrierZIF' as the card brand and look for 'OWC ZIF' next to the CPU speed or in the report comments.
Review Table of Contents:
Test Systems Used (and Why): I tested the Mercury ZIFs in the following systems (chosen for a reason as noted below):
Test Systems Hardware Summary
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Intro | Benchmarks | Appl. Tests | Software Controls | Docs/Installation | Specs/Design | Summary - or - |
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