Computer recognizes 8GB of ram, but only uses 30% of it?

some apps eg After Effects, Prem Pro, Cinema 4D will eat all the RAM you can throw at them.

snip here taken during a C4D render

Hi there

Thse applications tend to "Bypass" the normal OS -- usually to avoid any overhead in using OS processes. They also interact directly with the main hardware too.

These are very specialized applications. However things like MS office and 90% of what most people tend to run on their machines with the exception of Virtual Machines the REAL RAM will be managed by the OS and you probably won't see it taking too much of it at all unless running LOADS of concurrent applications.

This is why even a 2GB RAM machine is often more than sufficient for the vast majority of "Normal" computer users.

Cheers
jimbo

GeneO said:

A lot of photoshop operations write to its scratch disk no matter how much memory you have. For instance, if you convert a layer to a smart object it will write hundreds of MB to its scratch disk. Unless you have your scratch disk on an SSD with very fast writes, this takes 5 seconds, you can sit there and watch it! So I suspect something like that is happening. You can monitor the scratch disk for activity to see if the is the culprit.

Another example. I can write full speed to my scratch disk at about 100 MB/s. I have photoshop configured to use up to 5 of my 8 GB of memory. I just opened up a 10MP RAW image in PS CS5. That wrote about 100 MB to my scratch disk for about 1 second. I duplicated the layer. Another 100MB and 1 second to complete. I then smart sharpened the image. The scratch space jumped up 370 MB more or about 4 seconds to do the sharpening because of this. I am sure the sharpening itself takes no time, it is the writing to disk that does.

It is a real disappointment.

If I had the extra cash right now, I would get one of the new Intel 510 SSD explicitly for use as cache for Photoshop scratch, ACR and Bridge Cache, and Browser Cache. Maybe I would make it my system disk. But you need something that can do much better than HDD write speeds (>> 100MB/s) to see the difference. Many SSDs do not have write speeds that are any better than Hard disk drives. the Intel 510 claim to.

I should add how this relates to memory (I was addressing your "lag" above). I think Photoshop decides something is too big for RAM and writes it to its scratch disk - using les memory in the process/