Standard Disclaimer: I am not affiliated with M-Tech in any way, shape, or form. The opinions expressed here are mine.Introduction
The R581A is the first Socket-7 AGP complaint mainboard from M-Technology. It is based on the new SiS 5591 chipset. The recent hype and buzz surrounding the M-Technology’s latest Socket-7 offering has been phenomenal. The R581A’s claim to fame is an undocumented 90Mhz and 100MHz bus speed. Has the R581A won the Socket-7 100Mhz bus speed race that every Socket-7 mainboard manufacturer is vying for? Unfortunately, the answer is no. However, M-Technology has come closer than anyone has. Will 90MHz satisfy you? The R581A delivers a stable Socket-7 90Mhz bus speed and wonderful performance. M-Tech R581A Specifications:
Other Highlights:
SiS 5591 Specifications:
The Out of Box Experience
I had to resort to a Dejanews search to obtain the jumper settings. Incidentally, Dejanews is the most greatest technical support tool that I have used. It has saved me countless number of hours and support calls. Here are the undocumented jumper settings for the 4x and 5x clock multipliers:
Here are the undocumented jumper settings for the 90MHz and 100MHz bus speeds:
Note: Pin 1 is closest to the edge of the mainboard The R581A ships with the SiS busmastering driver, AGP driver/update, and system monitoring program (voltage, temp & fan speed) on two 3.5" FD. However, you need Win95 OSR2.1 (OSR2 with the USB update) as a minimum requirement to use/install it.
The Good ThingsThe first socket-7 mainboard to offer rock solid stable 60, 66, 75, 83, and 90MHz bus speed performance. PC100 8ns SDRAM is not required to achieve 90MHz. I used the default BIOS settings with 10ns SDRAM modules from Advantage and Macrotron without any problems. In addition, John Howland at Specialty Tech has run the R581A as fast as100MHz with 60ns EDO Micron memory. In my opinion, consulting with John Howland is like consulting with M-Tech. True PCI asynchronous mode at system frequencies above 75 MHz. At 75MHz, the user can choose asynchronous or synchronous mode. Asynchronous mode means that the PCI bus is running at 33 MHz and the AGP bus is running at 66MHz instead of 1/2 the system clock. Therefore, you aren't overclocking the PCI or AGP bus. This results in a more stable system because you aren't overclocking your peripherals. Asynchronous mode is part of the reason why the R581A can operate reliably at 90MHz.
One megabyte of L2 caches allows the R581A to cache up to 256MB of DRAM. One megabyte of cache is twice as much as L2 cache that ships with the majority of today's socket-7 mainboards. Supposedly, Cyrix has finished all of their testing on the R581A @ 83MHz and as soon as SiS supplies information that states the chipset is rated for 83MHz the R581A should be approved for the 2.5x83 6x86MX PR266. You can increase the CPU core voltage from 2.1V - 3.5V in 0.1V increments. This is a great feature for overclockers! The R581A has 3 x 168-pin DIMM sockets. SIMM sockets are finally starting to take a backseat to DIMM sockets with the increasing popularity of SDRAM. DIMM sockets and memory that utilizes them are the future. The more of them on a mainboard the better in my opinion. You will see an increasing number of new mainboards in 1998 that will not ship with any SIMM sockets. The Bad ThingsAlthough the R581A does feature 90 & 100MHz system frequencies, SiS hasn't stated that the SiS 5591 will officially support them. Many vendors are touting the R581A as the 100MHz Holy Grail. However, I haven't achieved stable 100MHz performance without turning off the L2 cache. Turning off the L2 caches results in a performance hit that is more significant than the performance gained by the faster 100MHz bus speed. The UpgradeThe R581A that I received was the latest revision (revision B2) and included an 8ns TAG RAM chip. The rev number is located next to the ISA slot farthest away from the PCI slots. The speed of the TAG RAM is marked and located just above the socket-7. The R581A was a very simple upgrade. However, I do recommend that owners of the R581A check the M-Tech website for the latest BIOS update. M-Tech has have been updating the R581A BIOS frequently because it is such a new mainboard. AGP video functionality was flawless. I didn't have any problems with SDRAM in a single or pair configuration. I also didn't have problems when I used a pair configuration with SDRAM modules from two different manufacturers. I didn't have a third SDRAM module to fill the last slot, but John told me that the R581A handles three SDRAM modules quite nicely. BenchmarksBenchmarks were performed on the following system. Here is a summary features:
Do you notice anything weird about the benchmark results? The K6 is consistently outperforming the equivalently rated 6x86MX. This is first time that I have seen this happen. I am still trying to figure out why. Yes, I had linear burst mode enabled. The R581A definitely doesn't seem to be optimized for the Cyrix/IBM 6x86MX. The K6/233 died @ 90MHz. I could not complete a Winstone 97 benchmark. The 6x86MX 75/225 didn't suffer the same fate. However, the 6x86MX 90/225 only produced a 1% increase in performance over the 6x86MX 75/225. I expected more. After confering with others, a rule of thumb is that the current revision (rev. B2) of the R581A will run @ 90MHz with either a K6 (if you are lucky) or 6x86MX (most likely success candidate) with SDRAM and the L2 cache enabled. Also Included in the table above are my first benchmarks of the IDT C6 WinChip. The performance of WinChip/225 doesn't look bad. However, the WinChip puked when I tried to use a 83MHz bus. It didn't like it at all. Expect my review of the IDT C6 WinChip to be published soon. I will tell you exactly where IDT wants its WinChip to fit in the CPU food chain and why. Key LearningsIn summary, the R581A is more like a 83MHz mainboard that will run at 90Mhz rather than a Super Socket-7 mainboard. M-Tech is currently working on getting it to run @ 100MHz. TAG RAM appears to be an issue. M-Tech is currently using 8ns TAG RAM and is looking for faster chips. An 8ns TAG RAM is fast enough for a 90MHz bus speed and 6ns PBSRAM should be able to handle 100MHz. In my humble opinion, the combination of features, stability, performance, and a functional 90MHz bus speed makes the M-Tech R581A the undisputed socket-7 champion - at least for now. Expect another title fight soon with the scheduled release of the first true Super Socket-7 mainboards. This page has been accessed |
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