bob@omni.com (Bob Weissman) (11/19/89)
I received some very good replies to my query about speeding up my tired old 8MHz XT clone. Executive summary: Many people were inclined to advise me to junk the ol' clunker and start fresh with a 386 box. (This machine doesn't get that much hard use to justify the cost of this alternative.) Nobody much liked the V20 or 8087 routes. A couple of people had good luck with accelerator cards, but others warned of incompatibilities. And an 8-bit bus is still an 8-bit bus. Motherboard swap was considered a reasonable thing to do. I haven't yet decided what I'm actually going to do; depends how much money I have left over after December's property tax payment and the Chri$tma$ $hopping $eason. Thanks very much to Dennis Lou, John F. Miller, Ken Hoover, Charles R. Meyer, John C. Archambeau, Paul Gomme, John P. Nelson, and ho@fergvax.unl.edu. Detailed responses follow. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - >2. Add an 8087-2. The effect of this depends on your software and computing tasks. It will have no effect on general operations. If your software supports the numeric coprocessor, you will see great improvements in math operations. >3. Add an accelerator card like the Orchid Tiny Turbo. This can provide considerable (100-200%) improvement in performance at the cost of a couple hundred dollars. Expect a few quirks now and then. >4. Replace the motherboard with a 286 or 386SX motherboard. This is a better choice than any of the preceding ones. A 286 board will cost about $200, or a 386SX about $400-$500, or a 386 from about $600 to $2000 depending on size (baby vs full size) and caching. Remember, though, that a slow hard disk can be a bad bottleneck, depending on your applications. >5. Any other suggestions? Keeping an old computer alive by gradually updating components is a lot like putting new and better parts in an old car. You're better off just buying a new 386 and doing something else with the old PC: -- sell it (even though you won't get much for it -- I originally paid >$3000 for my Zenith Z-150 XT, but I'd be doing great to get $1000 for it now. -- donate it to some charity and take a tax deduction (consult your accountant first). -- give it to somebody and forget about any tax deductions. -- use it for simple or dedicated tasks. I know one fellow who put a $200 Watson board in an old PC -- it makes the best darned answering machine you can buy. It also doubles as a word- processing system. The prices of new systems keep coming down. A ZEOS 386SX-16 with 32MB hard disk and monochrome graphics is now under $1700, and some barebones 386 systems are now under $2000. Really, the most cost-effective improvement you can make in your old PC is to just buy a 386. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Get an Intel inboard 386/PC for it... a 16mhz 386 AND a meg of RAM on an 8-bit card that replaces your 8088. It lists for $799, mail-order from several places is in the $569-$600 range. A hell of a deal for a 16mhz TRUE 386 machine. Of course, you'll probably want to get a bigger HD for it, too, but that's up to your personal preferences. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - I would recommend a replacement 286 motherboard that is specifically designed to use your old XT components. I have performed several upgrades and am very pleased with the speed increase for a very modest cost. Recently I upgraded my own machine with a Bullet 286 motherboard. It a 8 MHz machine that uses 120 ns RAMs. Since you have an 8 MHz XT I would recomment their slightly slower 7.2 MHz machine. It also includes RAM caching software built into ROM that if enabled and you have 1 MEG of RAM will use the upper 384K to cashe your hard disk and improve its performance. The cost of the Bullet 286E board was published at $125 in the most recent Computer Shopper and can be purchased from: Marchland International 1240 N. Van Buren Unit 108 Anaheim, CA 92807 714-630-3382 (just a happy customer with no affiliation) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - > 1. Replace the 8088 with a V20. Will give a 5-10% improvement in real applications. Do _not_ believe benchmarks, in particular the Norton Utilities. The V20 chip seems to do particularly well on the Norton Utilities SI. This is not indicative of its true abilities. > 2. Add an 8087-2. Do you do a _lot_ of math? I ran a little test once, and found that a particular application using an 8087 took 15-20% of the time as the same PC w/o the 8087. This was a very math intensive program (RATS, an econometric pacakge; it was flipping matricies and doing lots of matrix multiplications). However, I've found minimal improvement in using spreadsheets like 123, and doubt that you'd find any real improvement in word processing applications. > 3. Add an accelerator card like the Orchid Tiny Turbo. Now you're starting to spend some serious dollars. Why not save up for a real 286, or better yet a 386. > 4. Replace the motherboard with a 286 or 386SX motherboard. I've not done this, although I considered it. You _may_ have to upgrade the power supply at the same time, and you probably should replace your hard disk. As well, you may need to replace other i/o cards. > 5. Any other suggestions? What I did was to sell my old system (an XT clone) and go up to a 386SX. My old system was an 8 MHz XT, 40 MB hard disk, 8087, and the usual extras. The new system is a 386SX, 40 MB hard disk (28 ms), no 387SX, and the usual extras, and an extra meg of RAM (taking it up to 2 meg). The difference I had to pay was C$1400 (including tax), or about US$1200 at current exchange rates. You should be able to do better on your purchase price, and may be able to do better on the sale price, depending on how active secondary markets in PCs are in your area. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - >I've got an old XT clone which works fine, but is intolerably >slow (at 8 MHz). This is faster than the "original" xt, which ran at 4.77 Mhz. >1. Replace the 8088 with a V20. Well, this is incredibly cheap upgrade, but will only give you a 5% - 10% speedup. You may also find that some software will not work with the V20 (In fact, some powerup selftests in the BIOS don't like the V20, either) >2. Add an 8087-2. This only helps if you have software that uses a co-processor. With most software, you will not see a difference. >3. Add an accelerator card like the Orchid Tiny Turbo. This works ok. Depending on the speed of the accellerator card, you may see a 2 to 3 times speedup in cpu intensive code. Note that most of these things get most of their speed improvement by using "cache" memory: with the cache disabled, you may find that they run SLOWER than your current system (they usually only drive the bus at 4.77 Mhz so as to be compatible with all PC systems). You may find that devices actually run slower than in 8 MHz mode for this same reason (the controller card will not drive them faster than 4.77 Mhz). These things also require you remove the old CPU chip, and plug a cable from the accellerator board into the CPU socket. Some clones have different layout of components than the (assumed) IBM PC, so you may have trouble running the CPU cable. >4. Replace the motherboard with a 286 or 386SX motherboard. This works pretty good, although you need to be a little careful: The XT case is not as tall as the AT case, so some AT cards will not fit in the resulting system. Also, your hard disk controller card may be incompatible with the AT architecture, or if not, the 8 bit card will run much slower than a 16 bit AT controller card. Also, some clone systems do not have the same layout as an IBM PC, so a replacment motherboard doesn't fit quite right. If you are handy, you can usually work this out, however. >5. Any other suggestions? Yeah. Get a whole new '286 box (stripped). Use your current hard disk and display, and you can get a system pretty cheap. If you can get any money from SELLING your old system, I reccommend you do that, then buy a complete new system with a faster hard disk (which will better match the faster CPU). - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - > 1. Replace the 8088 with a V20. I did it. It helps a LOT with integer math and graphics applications (despite what that goofy Dvorak guy in PC Rag says), but doesn't help the rest of the system all that much. It still feels like an 8-bit bus, because it is. But then, it's only about 10 bucks. Whaddya expect? :-) > 2. Add an 8087-2. At well over $80, an 8087 is only worth the money if you spend most of your time doing floating point (e.g. cad, spreadsheets). I have one, and it was a bad investment, because I now mostly do word processing. > 3. Add an accelerator card like the Orchid Tiny Turbo. I've heard of bad compatibility stories with 286 plug-ins in general, and the Orchid card in particular. Plus, you've still got that 8-bit bus for a bottleneck. If you do mostly text-based applications like word processing or programming, no problem. If you're doing DTP, or using a graphical user interface like Micro$oft Window$, forget it. It'll help, but graphics will still creep. > 4. Replace the motherboard with a 286 or 386SX motherboard. That's what I'd do, if you have the money. Don't mess with the accelerator cards. -30- -- Bob Weissman <bob@omni.com> UUCP: ...!{apple,pyramid,sgi,tekbspa,uunet}!koosh!bob Hofstadter's Law: It always takes longer than you expect, even when you take into account Hofstadter's Law.