Reply 1 of 9, by Jo22
Yes - As far as I know, Windows 3.1x is said to do so, but not Windows 3.0.
Reply 2 of 9, by derSammler
Why would Windows use the FPU? If at all, applications may use it. Excel does it, for example.
Reply 3 of 9, by Jo22
It had been tested thoroughly in an article of win magazine, issue 5/'92.
Funny, though, that you mention Excel. The magazine said (by analogy):
"On Windows 3.0, co-processors lived a shadowy existence: Even by Microsoft's own estimation,
they were used for Windows applications such as Excel at best."
Reply 4 of 9, by konc
As far as I know they simply don't.
Reply 5 of 9, by derSammler
The article says Win3.1 does and gives up to 80% more GUI performance.
Reply 6 of 9, by Matth79
Windows calculator does - also on the Pentium .... we are Pentium of Borg, you will be approximated!
The thing is, what uses floating point - by the standard Windows function calls, it will be passed to the FPU if present, emulated if not
Reply 7 of 9, by Jo22
I forgot to mention - Microsoft once released a patch, WW0548.EXE, for systems with i387 FPUs.
Apparently, it was required for Windows 3.10 on 386 PCs and contained a new WIN87EM.DLL.
That dynamic link library does provide both virtualization and emulation of x87,
so multiple programs could safely make use of the math co-processor.
It is akin to WIN87EM.EXE, which was used in the days of Windows /386.
(Back then, it could be added optionally as load=win87em in win.ini.)
Anyway, 80486DX and 80486DX2 processors were excepted by that WW0548 patch..
I don't know if it was/is required for 286+287XL (i387 core) or 386+287 combos, though. 😕
Since the patch files in that self-extractor are dated mid-92, later releases of Win 3.x,
such as plain 3.11, WfW 3.10 or WfW 3.11, may already have shipped with a new DLL.
Reply 8 of 9, by keropi
I am resurrecting this thread because I did some quick tests on a 486slc33 system with and without a Cyrix CX83S87-33 fpu.
The rest of the system is 64kb L2 cache, CL5420 vga controller (NOT 5426/5428 stated on winmark) and 16mb of ram running wfw3.11 at 800x600/16colors.
so there is some boost in gfx speed - keep in mind that the 5420 does not really offer any gui acceleration, maybe a better vga sees no boost at all.
Reply 9 of 9, by Jo22
Thank you very much for testing, Keropi! 😎
What about the standard VGA drivers (3.1 and 3.0) ?
The 3.1 version does dirty-rectangle from what I remember, maybe it has some FPU code also ?
Anyway, just curious - since I have no physical 286/386 at hand now (all boxed up)! 😅