Recently obtained an fx-3600pv (circa 1989/90), which needed a bit of cleanup and repair (segment problems). Considerably faster than the fx-50F, with 38 steps and a bigger LCD display, but fairly stripped down in terms of features (No formulas, no constants).

The integration is a nice feature though and is well implemented for a Simpson version, including the trimming of inaccurate digits. It was hysterical that my fx-991MS 2nd Edition that came out last year is only ~25% faster and gives the exact same answer! (78 vs 62 seconds integrating e^(x^2) from 0 to 10 using 512 divisions). Of course now the newer integration technique that Casio uses is vastly more accurate and faster, though I was surprised at how well it works on this old fx-3600pv.

It has some bugs in programming as I verified having the same problem as in this rskey.org article:

http://www.rskey.org/fx3600pv
It also uses only 11 digits of precision (vs 12 on the fx-50f), which causes problems with Casio's weird rounding system:

https://translate.google.com/translate?h...ch&pto=aue
Basically if the last 2 digits + 11th hidden digit end in 001 -> 007 it rounds down to 000, which means for the number 1,234,567,800 any added decimals between 0.1 -> 0.7 don't count, which is just bizzare (you can add 0.7 as much as you like, but it wont change the answer). It will also do the same for 993 -> 999 except rounding up.

Also there isn't enough precision for handling powers, ie 2^33 = 8,589,934,592, but the fx-3600pv instead returns 8,589,934,589 which is off by 3, exceeding Casio's stated accuracy of +-1 digit on the 10th digit. This isn't just a problem for the fx-3600pv, but seems a widespread problem with any of the old Casio's using 11 digits of accuracy (verified on the fx-550s and the fx-82LB - though that is only 8 digits, so not so much of a problem).

In any case, probably too much commentary, here are the figures:

Summation Benchmark n=10:
Average of 3 tests (Degrees): 6 seconds

Result: 13.711835009

Summation Benchmark n=100:
Average of 3 tests (Degrees): 58.9 seconds

Result: 139.2971869

Summation Benchmark n=1000:
Test 1 (Degrees): 573 seconds

Test 2 (Radians): 574 seconds

Result: 1395.3462707 (same for both tests, whether degrees or radians)

It's much faster than the fx-50f (~3 times), but it isn't as accurate.

EDIT: I should add that this was well lit, next to the window on an overcast, but bright day. While I also have a brand new silver oxide battery in both the fx-50f & fx-3600pv, it does take longer when moved away from a light source (~74 instead of 58 seconds on my desk just testing now). It was also mentioned above that in some cases the cube root vs the x^(1/y) power function can produce different results, but they seem to be about the same on this old Casio. The square and root function are actually much faster on the Casio then using the x^(1/y), but that wasn't used for this benchmark.