386DX-40 Upgrade! Texas Instruments 486DLC-40 and a Rare Cyrix 486DRX2-66! 

I was in IT at the time. The issue with the 486dlc/slc was the many companies that sold them as if they were full 486dx/sx. In many cases, especially the local computer stores would sell them for close the the same price as a full 486 system. There was one computer company in the county that lied to customers about what they were buying and used only the cheapest components. I personally know what they did because I worked for them for about a month until I could not continue . If I remember correctly the owner's special was a 486slc with 2mb ram, the cheapest 512kb video card and the cheapest smallest hdd. The motherboards were horrible. He charged something like $1200-1500 for that junk.

All three of these chips were produced at the TI wafer fab in Stafford, Texas when it was operational.

Cyrix drx2.. these are memories lost, thank you so much for bringing em up alive, it's like founding a piece of youth lost

I've got a few boxed DRx2 chips, which I got a long time ago from e-bay. They all came with those green heatsinks, which were contained in the package, but not placed on the chip itself. They came with a self-adhesive thermal pad, so it's a stick-on.

Had a AcerPower with similar socket arrangement, a soldered 386sx and a 486 upgrade socket. Also needed the soldering iron to get up the clockspeed, had to replace the crystal to max it out. Intresting video suggested by "the algorithm" :)

Had the 486dlc when I was growing up it was the first computer we had on the internet

I overclocked one of these when I was 15 (1995). They do tend to run really hot, especially when overclocked! :-) Love playing arount with these upgrades. Takes me back to the nineties when it was actually fun to fiddle with hardware. Such exciting times! Recently aquired a bunch of these upgrades. I've got an old, very nice 1990 NCR Model 3300 with an 386SX-20 which I'm going to desolder. It will get a 5V Ti 486SXLC2-40 instead. And my favourite eighties machine, a 1988 Compaq Deskpro 386/25, huge heavy beast of a machine which cost 20.000 USD in 1988 (!) is now running a Ti 486DLC-25, is receiving a rare Improve Technologies Make-it 486, which is the rare PGA-132 Ti486SXL2-50 with 8k of L1 cache and a sketchy soldered on cache coherency circuit, which is a drop in replacement. Awesome! 👍👍 Also have an IBM Blue Lightning 486DLC3 running at 75Mhz with 16k of write back cache, which is a very weird machine (PS/2 Model 56i SLC3) because it has a 'neutered' 32-bit IBM DLC3 CPU with its databus cut in half, effectively making it an SLC3 with a 16-bit databus, supporting a maximum of 16mb of RAM :-) Keep up the good work. Really enjoy your videos! 👌

You are very much limited with the used graphics card. Either you are using some card wich is too slow, or your wait states are not set to 0, or your ISA bus divider is too slow. I have a similar board and it is possible to squeeze about 6000 characters per second in Landmark (you have about 2,5k) with a good graphics card and optimized settings on 386DX-40. Especially for the graphics related tests, which you are doing, it is important to get everything out of the ISA bus and the graphics card. Just to avoid any bottlenecks impacting the CPU.

My first PC was a AMD 386 DX40 just like this one (without the 486 socket). :)

Excellent video! Did you know that this is a PCCHIPS actually? Removing the SARC sticker you can see it. It's a fast little board. Mine appears to be from 94. Very late in the game for a 386. I suppose they were selling them as budget systems. Nice Cyrix processors! Maybe a jumper or a dip switch somewhere on the board could be a definitive solution to install them.

The Austalian military went down the cyrix 486slc route as I remember the RAAF/Cyrix partnership advertisements in the various computer magazines here, and yes, they all came with the green heatsink fan here.

The Texas 486 DLC has 8Kb of L1 cache, which made it faster in actual games when compared with the Cyrix DLC. Also, used to sell systems with those cyrix DLC chips on. So many of them died from heat a few months in that Heat sink became mandatory item. If your CPU has been run for any significant time without a heatsink then it could be damaged goods now. It looks in pristine condition, so maybe previous owner(s) ran it without heatsink and damaged it. The few minutes you used it for aren't likely to have been to blame here. Those chips all ended up coming with mint coloured heatsink. TEXAS do a clock doubled dlc as well, which also had 8Kb L1 cache performance was slightly better than Intel 486SX-33

Wow, I have the exact same motherboard (which is a PcChps btw) and I also have a Cx486DLC and TI486DLC that didn't want to boot. Been investigating it for ages and now I know how to fix that. It's stupid that they didn't include a jumper to select which processor to boot, if the soldered one or the socketed one, if installed. Awesome video!

5:10 - there certainly were some strange ducks back in the day. It's so inexplicable why they'd ever solder on a socket that can't even be used LOL

It´s a PC-CHIPS M326 - i am soon getting the same Board with a DX40 too but will have to check the faulty Keyboard Controller.

Super awesome video man! Didnt know you could have such a small 486 board.

I did the same on my 326 V5.2 pin 54 and 55, thaks a lot my friend!

I have a Cyrix 486DX2 for a 386 16mhz socket on a ibm ps2 model 80... so retro now!

If you don't use the Cyrix utility then the on-chip level 1 cache of the DLC (and possibly the DRx2 too) won't be enabled. Enable it and you will find your benchmark results will be substantially higher. None of your boot screens showed the tool running - did you enable it afterwards?

Wow, what a blast from the past! The very first computer I attempted to build myself from loose pieces at age 9 was in fact a TI branded 486DLC. The motherboard I had did not have any provision for a onboard processor, but did come with a 486DLC/40 installed. I had thought I was getting a real 486 for bargain prices, how wrong I was! It ended up being the most unstable hot running piece of junk ever! You could seriously burn yourself if you had it running for any length of time and glanced a finger across the ceramic. I had to affix a heatsink and fan to it in the most awkward way, as it was unbearably hot. I recall thinking this was because the voltages or something were set wrong, but everything checked out. It threw parity errors at random, froze up constantly (especially in windows), and never ran well for me. Doom was a guaranteed failure to run. I thought it was the ram, so I replaced it, I double and triple checked my jumper settings (and changed them to all sorts of things when logic failed), swapped the power supply and graphics card, messed with every bios setting known to man, and nothing made that machine even close to stable. I really thought it was cursed until I found a AMD 386DX/40 in a trashed motherboard during a raid of my computer store's board bin (located in the back of the store in a bathtub full of random motherboards and ISA cards) and when I put that in the motherboard my entire world changed and the computer felt transformed. It was stable and awesome after that, and it never gave me trouble again. I had nothing but awful things to say about any CPU branded Texas Instruments after that to anyone who would listen. Maybe I'll see if I still have it and see if there's something 9 year old me missed. I suppose it's possible I ended up with a bunk/bad CPU, or missed some important configuration step I suppose.

You can start heretic by adding the "-debug" command. That will also make it run on a standard 386DX-40. I did that back in the day, and enjoyed the shareware ... It was a slideshow - but I didn't care .. I still played it.

11:18 I have an explanation for the heat sink dilemma. The Cx486DRx2 came in 16/32 (has no heat sink), 20/40, 25/50 and 33/66 these 3 had a green heat sink with the matching model printed on the heat sink however these had same thermal properties as the 16/32 one which means they only needed the heat sink if the bus speed was equal or more than their rated bus speed. In other words, if you find a Cx486DRx2 20/40 in a 386 which has 16MHz bus then yeah they probably dropped the heatsink as it won’t be necessary. That Cx486DRx2 20/40 however is going to be working as 32MHz (max). Pretty confusing when I was researching them 😂 Note: 16/32 means, the first speed is the motherboard speed 16 and the second speed is the processors internal clock speed 32.

My very computer was an IBM Aptiva 486 SX2 50mhz when I upgraded it to a DX2 66mhz I felt like a king😂

Nice! I have the same board, but the socket is not soldered.

Nice video. Thank you sir

Reaaallly wish you'd shown us a difference in Doom gameplay. Probably pretty great.

heretic was one of my favorite games back in the day, used to play with my friends using IPX and was hours of fun killing each other. I still play it solo using dosbox these days.

I love 486.

Maybe the voltage is dropping due to higher power consumption? Adding a volt meter or oscilloscope to see if the voltage close to the CPU is dipping under load, could be worth a try. If some, maybe adding some capacitors or extra power wire to lower the resistance, could help. Or lowering the voltage to lower the power usage. The board probably is simply not prepared to run this CPU. I don't think the CPU is damaged.

I've got that trident graphics card and that ti486dlc. My motherboard looks just like yours too but there is no 386 soldered to the board, but there are pads for it.

instantly subscribed. also i think you can plug in a normal 486 and it should work. at least in old IBM pc it did.

I upgraded with the Cyrix, it had a green heat sink as I remember 👍

I had a Cyrix 486 and I'm pretty sure it had a loose heatsink with a tension clip that held the heatsink in place when attached to the motherboard socket. I could be wrong. But I guess that wouldn't help in your case since your motherboard is much different.

This is the nuttiest thing I've seen

486 all had heatsinks - mine anyway- and like the smallest possible fans also -attached with plastic clips

Thanks for the great video, this is the only video showing the drx2 I have a question which is the best cpu you recommend to upgrade an Intel Inboard 386/pc is a board? It has a 32MHz crystal and a 386 DX running as 16MHz by default. I like to get the max out of an XT computer using this card. The intel inboard does wonders for an XT but I was wondering how to push it to the limit! There are tons of mods online but it requires transcomputer models which are impossible to find. I don’t mind swapping the crystal and from what I researched the intel inboard does run stable at 40MHz crystal which means a 20MHz 486 could be used. The socket is 132 I believe. I appreciate your help so much! Your videos are the best!

The drx2 needs heatsink (and was sold with ) for all models upper than rhe 16/32 series and need a software to enable the right l1 cache mode

It's a PC Chips board, which you can tell by the sticky labels on the chipset. Luckily, their 386 boards were fine. Don't get any 486 and newer stuff of theirs, though; it's all junk.

You can use needle If need short two pins to test it.

Dlc was designed to update the 386 to 486 with 16 bit bus

That chip requires a heatsink.

Ehm. There's no such thing as FPU in a 386 with out one being socketed in the FPU socket, you need atleast a dummy chip to bridge the traces so it can use the in CPU FPU... So, eh, yeah. You're missing alot. Just by not having it enabled. :D From WikiPedia: "The 486DLC can be described as a 386DX with the 486 instruction set and 1 KB of on-board L1 cache added. Because it used the 386DX bus (unlike its 16-bit cousin, the 486SLC) it was a fully 32-bit chip. Like the 386 and 486SX, it had no on-board math coprocessor, but unlike the 486SX, it could make use of an Intel 387DX or compatible numeric coprocessor. A few 486SX motherboards also provided i387 sockets, but this feature was a very much a rarity. Due to the smaller L1 cache, the 486DLC could not compete on a clock-for-clock basis with the 486SX, but a 33 MHz 486DLC could keep pace with a 25 MHz 486SX, cost less, and offered the ability to upgrade further with the addition of an inexpensive math coprocessor. While some advertisements in PC magazines from smaller manufacturers touted the superiority of their 486DLC over name-brand computers sporting a 486SX, in reality the only advantage the 486DLC offered feature-wise over the 486SX was the ability to add an inexpensive math coprocessor. The Intel 487 "math coprocessor" for 486SX users was in reality a CPU replacement-a 486DX with a different pinout-and originally cost several hundred dollars more than a 387. As prices on Intel's 486 line fell, Cyrix found it more and more difficult for its 486SLC and DLC CPUs to compete and released a fully pin-compatible version of the 486SX and DX in 1993. Cyrix Cx486DRx² microprocessor Die shot of Cyrix Cx486DRx² The 486DLC did not see widespread use among large OEMs, but it was widely known among the hardware enthusiast community that an AMD 386DX-40 or Cyrix 486DLC-33 could keep up with a 486SX-25 at a lower cost, so it gained a small following among budget-minded enthusiasts. It was also sometimes used as a replacement for a 386 CPU to give a small speed boost. However, the 486DLC was not designed to be a direct CPU replacement and could lead to stability problems in older boards it was not intended for. "Cyrix" aware motherboards usually had a few extra cache control lines to maintain cache coherency, as well as CPU register control in the BIOS to enable/disable the on-board cache. Cyrix later released a clock-doubled "direct replacement" upgrade package for 386DX systems called the Cx486DRu2. This kit included a standard 486DLC with an extra "dingus" that sat between the CPU and socket and provided the control lines for cache coherency. These kits were quickly superseded by the Cx486DRx2 CPU, which integrated the cache coherency circuitry into the CPU itself. The Cx486DRx2 appeared on the market in 1994, by which time the 486 was already being displaced by the Pentium. Sales were poor due to the high price and the underwhelming performance compared to a true Intel 486DX2. It was often cheaper to purchase a new 486 motherboard than to invest in an upgrade CPU.[1]" Yeaah, I'd be looking for a IEEE754 compliant Xilinx FPGA image and adapter. Make that Pentium FPU the bitch it always was. Also, lack of cache coherency, will hamper performance if the BIOS isn't capable of enabling this feature, I guess a CLI program to tickle appropriate registers will mitigate this, if BIOS isn't co-operating and tickling the CPU approapriately. So, I guess, I'd retrace the CPU into a FPGA as well. Since, Cyrix silicon tended to be a finicky partner in the first place. Unless it was debugged and fabbed by IBM, in which case, it's known as the Blue Lightning. :D

No prendio al principio, por que el 486 dlc utilizan si o si como ayuda el coprosesador matematico. Sin tener puesto el coprosesador pasa que no enciende

Hi My guess is the mother board is a bit of a combo design - ie mass produce a board that can cater for 2 or 3 different processors - depending on the next assembler / reseller - the benefit is one board, then "pick a chip" and make a PC , that way they can produced from 386SX - 486 DX but using as many identical components as possible If the chip is that hot then it needs a heatsink - coolers did not exits until early Pentium ( i have a P-1-100 that has a tiny clip on fan - from memory AMD 6 and cyrix all needed fans) I believe you have checked voltage most 386/486 run on 5 volt but newer chips were designed for 3.3 volt You can view comparison information from Phils web page Benchmark programs www.philscomputerlab.com/phils-ultimate-vga-benchmark-database-project.html Benchmark visitors compiled results www.philscomputerlab.com/phils-ultimate-vga-benchmark-database-project.html Regards George

Why is Sysspeed 6.0 showing CPU Clock, 141MHz? It looks like it is not looking for this information in the BIOS, or the CPU registers, but maybe runs some simple code to estimate the speed? And because the CPU is highly pipelined it gets things wrong, because it was calibrated on 286 or 386 probably? Still, I don't think there is any way to make the 486-40 to actually do more than 40MIPS, no matter what you try in terms of instruction mix. I think the Sysspeed have some weird multiplier for their measurements, which is kind of misleading. Marking it with "MHz" just makes it worse. Also the BIOS knows the speed from somewhere, probably from the bus information / jumpers.

(4:38) pin 54 ? What datasheet are you using?

No doom test;(

The rx66 has slower video performance.

Those are not "expansion slots". Expansion slots are 16 bit ISA at the left and back corner of the board. Those are SOCKETS for processors..... Like "socket 7". Those are NOT expansion slots.

Du musst mit alten Computern mit einem alten Anzeigen nutzen.

My 386DX-40 gets a 3.6 on PCplayer, i think your video card might be a bottleneck.

I think your video card is bottlenecking this system. I had once an 386DX-40 system, tested with a fast VGA card (Tseng ET4000AX, and CL-GD5422) it was able to reach 15,0 fps in 3DBench, and 4,1fps in PC Player benchmark.

You should just de-n00b and use a fucking heatsink on them. Why run them without one? Just stupid.