64bit vs 32bit memory usage

[paul878]

Doe 64bit OS and application use 2X the memory as 32bit?
8G of memory in a 64bit environment = to 4G of memory in a 32bit environment?

 

[lxskllr]

No. It'll use slightly more memory, but not enough to matter in a modern system.

 

[CrystalBay]

It also feels to run a bit smoother ..imo

 

[masteryoda34]

In 64bit systems the size of a pointer may be larger, which causes an increase in memory usage vs 32bit.

 

[KeypoX]

Google it pretty sure its been documented plenty. I think its a couple hundred MB. Significant but not that big, if you had 3.5GB of ram than 32bit would prob give you the most free ram.

 

[Nothinman]

Doe 64bit OS and application use 2X the memory as 32bit?
8G of memory in a 64bit environment = to 4G of memory in a 32bit environment?

Nothing with regards to memory management is that cut and dry. How much extra memory a 64-bit build of an app will use compared to the 32-bit build depends on how it's programmed. Pointer usage, memory types, etc. The difference could be anything from a handful of bytes to megs or even gigs I suppose. I would say that 10% might be a good random guess to start with and then do some real profiling of any apps you use if you really need to know the difference.

 

[Griffinhart]

An App or OS being 64-bit doesn't mean that they will use more ram, though they often do. But 8GB on 64 is not the same as 4GB on a 32. A 64-bit OS running 32 bit Apps will use similar resources. At least not enough to make any noticable difference.

The real difference between 32 and 64 bit is how much RAM the OS and Apps can address. In Windows, 32 bit can address and use up to 4GB (roughly) and applications up to 2GB. You can have 8GB of RAM in that machine, but it won't make use of it.

A 64-bit OS can address and use much more and 64-bit apps aren't limited to 2GB. It's a noticable improvement for Apps like Photoshop where images can often eat up tons or RAM.

 

[Nothinman]

An App or OS being 64-bit doesn't mean that they will use more ram, though they often do.

Although the difference varies heavily by application, it sure does. Larger pointers, more registers, etc mean the binary will be slightly larger and it's memory usage will be slightly higher as well. For most apps the difference is minimal, but there is a difference.