>>I have just increase my RAM from 64m to 128m
>>Using NT4 Work Station
>>VFP6
>>UT Navigator seems to have slowed to a crawl when adding new messages or adding unread messages.
>>Cant find the reference, but seem to recall that this is a known problem, but what does one do to fix it.
>>In Addition the "System Idle Process" in Task Manager seems to be taking huge amounts of CPU cycling about 2 times a second.. This only seems to occur after using VFP.
>>
>>Any ideas ?
>>TIA
>
>Are you using a Pentium precessor. The Intel chipset used with these processsors can only cache the 1st 64MB of memory. Since the operating system loads into high memory it runs uncached and the system crawls. If you are using a Pentium Pro or Pwntium II the limits are 4GB or 512MB respectively. The only way to speed up the Pentium is to remove the extra memory and hope you can return it.

It's not processor related, but chipset related. Other Socket 7 and Super 7 family processors, which use external L2 cache, are subject to the limitations of the motherboard's cache controller and L2 cache configuration. Of the Intel chipsets, only the 430HX and 430TX chipsets supported >64Mb of RAM; the 430TX was subject to an L2 cache address limit of 64MB.

A 430HX chipset with a second tag RAM, or any of Via's or ALI's (now Acer) chipsets can cache the entire address space supported by Socket 7. The Pentium chip itself only manages the L1 cache, and can internally cache the entire address space, but the L2 cache is managed externally, which is where the 64MB cache address space of the TX comes from. The old 430VX and 430FX chipsets could only address 64MB in any case; the HX (the second to last chipset produced by Intel for Socket 7 processors) was the real gem of the family; the only real benefit found in the later TX was SDRAM support, and the introduction of UDMA to the IO support chip.

The current crop of Super 7 motherboards, which can support the Intel Socket 7 processors as well as newer Socket 7 compatible chips like AMD's K6 and Cyrix's M2 processors can cache the full address space, and in some cases support very large L2 caches (some of the Via chipsets support up to 2MB of L2 cache). With the price of Super 7 motherboards under $100 in many cases, I'd look to move the processor and memory to a new motherboard, which would also give some possibility of processor upgrades in the future.

The address space limit on the Slot 1 Pentium II processors (Pentium II and Celeron) is chipset related as well - the 440 family prior to the 440GX could only address 512MB of SDRAM (the BX chipset could address up to 1GB of unbuffered EDO, but there, the performance hit when compared to SDRAM is prohibitive.) The 440GX chipset, which can support both Slot 1 and Slot 2 (Xeon) processors have a larger address space and cachable address space. I believe there are address space limitations on the low-end EX and some of the new Socket 370 support chipsets from intel as well.

Both the current Celeron and upcoming Socket 370 Celerons have limited external address lines - even if the chipset supports more memory, the processors are limited in how much RAM they can address. This is one reason I recommend against using motherboards designed around Intel's low-cost Celeron processor specific 440EX - the 440LX and 440BX are completely capable of working with the SLot 1 Celerons, and have only a marginal difference in cost when compared to the dain-bramaged 440EX.

All the chipsets from Intel that are designed to support the Slot 2 processors will support better than 512MB of RAM, and the L2 cache supports the full range of memory addressible by the processor. And Intel is now shipping Xeons with up to 2MB of L2 cache on the processor; the 450NX in two way and four way processor configurations can share the L2 cache between processors to some extent.

The best resource I'm aware of is Tom's Hardware Page, which has comprehensive discussions of the capabilities of both chipsets and processors that don't require an EE degree to understand. It has a tremendous set of links on systyem optimization, BIOS setsttings, and hardware vendor pages as well.