Windows 7: 64 or 32 bit?

[Altera_Forum]

How does Quartus perform on Windows 7 64 bit vs 32 bit? I am using a Dell D820 laptop with 4G RAM. 

 My XP installation is showing all the signs that it is time for a clean install, and I figure I may as well jump to Windows 7. 32 or 64 bit - what do the experts say?

[Altera_Forum]

if you have 4gb of physical ram, windows only actually sees about 3gb because of device addresses. Also, newer altera devices need a minimum of 3gb to actually compile, so 64bit is a must.

[Altera_Forum]

Thanks, Tricky. I should perhaps add that my projects are probably small by your standards. Currently I am using up to 40k LEs in Cyclone II. Next is probalby around 70k LEs in Cyclone IV. I suspect your point is still valid.

[Altera_Forum]

Do you have extra slots for more RAM in the future? If you do, the best solution long term would be to just go to Win7-64bit, but still use Quartus 32bit executables. The advantage is that you will be able to use the full 4GB of RAM for Quartus, instead of the 2GB that win32 limits you. Of course, Win7-64 will use more of the 4GB of RAM for the OS, so you will waste some memory there.  

 But RAM is getting very cheap, so if you could add an extra 2GB or 4GB later on, you will have the flexibility without having to re-image.  Hope this helps.  -David

[Altera_Forum]

Thanks, I have W7-64 running and installed the 32-bit executables - because that's what I had. I am curious: why not the 64-bit excutables?

[Altera_Forum]

The 64-bit executables are fine too, but they will use more memory (every pointer in memory requires 64bit instead of 32bit), so if you only have 4GB and you are only using Quartus for small designs, why waste the little memory you have.  

 In general, there is no benefit in using the 64bit version unless you need it (again, because your design needs the 64bit address space). But running the 32bit EXE on a 64bit OS is still an improvement as Quartus gets to use the full 4GB (2^32) if needed (instead of the 2GB that win32 limits).   On the side, note that Linux32 does not have the 2GB limitation, and Quartus 32bit exe can use the full 4GB on Linux32.   Hope this answers your question

[Altera_Forum]

Thanks Davka! It is clear and very helpful. Much appreciated.