Wanted processors and co-processors

I'm looking for rare chips (processors, co-processors) listed in the table below. In addition to them I'm looking for different kinds of processor samples: engineering samples, customer samples, mechanical samples, thermal samples and marketing samples (see the table below for more information). If you happened to have one or more processors or co-processors from my wanted list please contact me. If you have any other chips (not from the list below) and you'd like to find out how much they are worth please see CPU price notes on the bottom, or post in the forum.

If you have any datasheets in electronic format, or if you have data books for you no longer need them please check my list of wanted datasheets.

Wanted: Rare microprocessors, co-processors and microcontrollers
Family	Manufacturer and part number
4004	Intel MCS-4 set National Semiconductor INS4004D in white ceramic package National Semiconductor INS4004N (plastic package)
4040	Intel C4040 Intel C4040 ES Intel D4040 without copyright line Intel MCS-40 set
6502	MOS Technology 6502 or MCS6502 in white ceramic package
8008	Intel 8008 Intel 8008-1 Intel G8008 Intel M8008 Intel X8008 Intel 8008 or 8008-1 in plastic package Intel 1820-1221 Microsystems International MF8008 (without suffix 'R') Siemens SAB8008-1D
8080	Intel 8080 (part number without prefix) Intel C8080 Intel C8008-8 Intel C8080C Intel C8080C ES Intel D8080 Intel MC8080 Intel MC8080A Intel MC8080A/B Microsystems International 8080 Mitsubishi M58710S Siemens SAB8080-C Siemens SAB8080A1C Siemens SAB8080A2-C
8087	AMD 8087 (if it exists) Cyrix 8087 Intel D8087-3 Intel D8087-4
IDT Winchip 3	Any speed
K6	Black top K6 processors - any speed
K6-2 (K6-3D)	AMD K6-2/250 AMD K6-3D 250
Nx586	Nx586-P75 Nx586-P133 Nx586 Nx586 PF100-E/E Nx586 PF110-E/D Nx586 motherboard with Nx587 socket
Nx686	Nx686 any speed (with motherboard if possible)
Pentium	Pentium 50 MHz (probably A80501-50)
Rise Technology MP6 II	Any speed
Weitek 4167	Any speed, in original box
Wanted: Microprocessor, co-processor and microcontroller samples
Engineering sample	Usually marked "engineering sample", "eng sample", "eng eval", "es", or "sample" on the chip top, and sometimes on the chip bottom. Some Intel 80486 and Intel Pentium processors are marked with "ES" on the bottom - these are not samples unless there is an "ES" marking on the top of the processor.
Mechanical sample	Marked "mech sample" or "mechanical sample".
Customer sample	Older Intel processors were stamped with "CS" on the top of the chip. The "CS" letters usually differ from other markings on the chip - they may have slightly different color and font.
Thermal sample	Usually marked as "Thermal sample"
Marketing sample	The processors that look similar to pictures in press releases and official product announcements. These usually have a nice looking company logo and/or product (family) name. Marketing samples don't have any specific information about the chip - speed, voltage, etc.
Please contact me if you have chips from the list above, or if have samples of any old microprocessors, microcontrollers or co-processors.
Prices of collectable CPUs, microcontrollers and other chips.
The price of the chip depends primarily on chip rarity, collectibility and condition. Chip rarity is based on how many chips of the same manufacturer with the same part number and in the same package are available on the market to collectors. Chip rarity is usually related to chip age - older chips are more rare, but there are exceptions to this. Other factors affecting the rarity: Package - plastic packages are common, ceramic packages are more rare, purple/grey side-brazed ceramic DIP packages are even more rare, and white ceramic packages are the rarest. There are exceptions to this - for example, purple ceramic Intel C8087 is more common then Intel D8087. Another example - C8008 in plastic package is much more rare than C8008 in ceramic package. Variations in chip markings - old / newer company logo, font size, location of the markings, unusual markings or family logo, and so on. Variations in chip package - tin or gold pins, type of the lid, square or rounded lid, additional marks on the package (for example, "5" on white ceramic C4004), etc. Sample chips - engineering, customer and other samples are valued much more than production parts. The samples are usually valued a few times higher than production chips, and in some cases 10-20 times higher. Please see "Wanted: Microprocessor, co-processor and microcontroller samples" section above for information on how to identify engineering, qualification, mechanical and other samples. Please note that modern (Pentium D, Core 2 Duo, Phenom and others) engineering samples have much higher market value than their collectible value - if you have one of these processors you'd be better selling them to people who actually use them than to CPU collectors. Collectibility - how desirable this chip to CPU / chip collectors, or, basically, how big is the chip collector market for this specific chip. The biggest market is for microprocessors. The market is slightly smaller for Floating Point Units (FPU), and even smaller for bit-slice processors, microcontrollers, and first RAM / ROM and support chips. There is almost no market of old support chips, and very small market for modern processors - they are not considered collectible yet. From manufacturers collectors usually favor Intel. Condition - New / used, quality of chip markings, the presence of scratches / chips on chip surface, condition of pins, working status, etc. New chips in working and visually like new condition are most desirable to CPU collectors. Used socketed chips have lower price then new chips, and used soldered chips have much lower price (about 50% price of the new chips or lower). Damaged chip markings and scratches, marks, and especially surface chips may lower the price even further. Non-working chips are usually worth much less than working chips. For boxed processors or FPUs the price is also determined by whether the box is in original shrink wrap or not, and the condition of the box. Unopened still in shrink wrap box in like-new condition is worth more than opened box, and much more than badly damaged box (even if it was not opened). Supply and demand for different chip types always fluctuate, which results in constantly changing chip prices. For example, in the recent few years we've seen many non-common processors and floating point units sold by collectors and sellers from Asia, where those chips are recycled, which reduced the price of many 8086 - Pentium class processors. At the same time due to limited supply the prices of some 4004 and 4040 processors went up. Because of the constantly changing supply and demand for chips and huge number of different chips variations, publishing up-to-date chip prices is not physically possible.