I've got that CPU with glued heatsink and couldn't identify it first, but it just worked, so I convienced myself that there's no need to detach that heatsink. Later as I switched 486 CPUs between my mo-bos this little fellow happend to be placed right after the DX2 in a than-unused mobo. Today I've powered that rig and found it working fine, and what is more interesting, it even passes tests with results comparable to DX2/66. I got curious what's under the heatsink (like, maybe SL-enhanced pard, or something), finally got it off, and literally was stunned - a plain old DX/33. Curiously, it looks like SX829 is the latest stepping for DX/33s: http://www.cpu-world.com/sspec/SX/SX829.html .

Even more interesting fact, as I first tried to identify the chip by it's markings underneath, i've stumbled upon a collector here: https://sites.google.com/site/alexanderhere/collections . He posses an i486 A88486DX-50 with quite similar markings underneath 'A4 ED 38' and, i'd say, a very close number of 93292384CB.