2gb Ram - Enough for win7 ?

[ashetos]

Correct me if I'm wrong but disabling the superfetch service does not mean there is no prefetching taking place in the SSD drives by the operating system.

As far as I know superfetch tries to predict and preload specific files/applications before you use them, according to your past habits.

Prefetching is something more generic, for instance let's say an application reads the first 512 bytes of a file and the OS prefetches 128KB or something like that, predicting some kind of sequential access pattern and trying to reduce the total number of I/O requests and the I/O response time if possible. This is especially effective when accessing large files like a movie file.

As far as DRAM caching is concerned, I have measured in a linux VM a throughput of 9GB/s for accessing a DRAM cached 1GB file. This means that in linux, DRAM caching is at least an order of magnitude faster than an SSD drive, and that is not even a native execution!

Now, as far as Windows DRAM caching performance (NTFS) I did the following. I accessed the same file in the linux VM (virtualbox), but forced raw device access in linux. However, the VM image was set in virtualbox to be used as Host I/O cacheable. This resulted in 1.7GB/s throughput. That means, a guest linux VM application accessing directly a virtual disk going through disk emulation and finally ending up as Host NTFS file requests. Even using a VERY heavy I/O path that leads to DRAM caching surpasses speeds of SSDs.

My conclusion is that DRAM caching is not going anywhere in the near future, SSDs are not that fast yet. This is one way that 32GB of RAM can help improve I/O performance. DRAM caching is usually twice as fast as a RAM disk because RAM disks perform an extra memory copy to emulate a real block device. The caveat is, that this applies for read only workloads, because if you're modifying files, at some point they are going to be flushed to the backing storage. This is where RAM disks excel, they postpone writes up until system shutdown and do not involve any real disk IO whatsoever.

 

[Cerb]

I haven't installed any SSD software like that. It's possible that the AMD AHCI driver did it, but I don't think I've seen a third party driver mess with a core Windows service before.

IIRC, it's WinSAT.

Correct me if I'm wrong but disabling the superfetch service does not mean there is no prefetching taking place in the SSD drives by the operating system.

As far as I know superfetch tries to predict and preload specific files/applications before you use them, according to your past habits.

That's Superfetch, which used to be called Prefetch. The registry entries are still named as for Prefetch.

Prefetching is something more generic, for instance let's say an application reads the first 512 bytes of a file and the OS prefetches 128KB or something like that, predicting some kind of sequential access pattern and trying to reduce the total number of I/O requests and the I/O response time if possible. This is especially effective when accessing large files like a movie file.

Read-ahead, and also it's companion, write-behind, are the more common terms for that.

 

[Z15CAM]

Win7 32-Bit with a Single or Double Core Processor at say a 2200+ Mhz = YES. It will not be soapy unless your running a Dual Core at 2500 MHz CPU with 3GB'B's of 400 Mhz DDR Cas 2.5 or less on a 7200 rpm ATA 133 HDD.

 

[mikeymikec]

I've upgraded some fairly old PCs recently (two at the customers' request rather than my recommendation for what they ought to do), and Win7 32 seems to run pretty well on them.

One was an Athlon 64 3200+. I was on a pretty easy-going budget with this one, so I upgraded the RAM to 3GB. It had a dGPU already so I left that alone, but had to replace the HDD because the old one was full, so it ended up with a WDB 1TB. For the basics it seemed passable. There were times when it showed its age, like when doing a load of Windows Updates for example.

The other one was a P4 3GHz from 2005-2006. I upgraded the RAM to 2GB total (tighter budget), put in a new dGPU after noticing that the video RAM was entirely used up (32MB ATI X300 PCIE... odd combination) as soon as Windows had started, and a WDB 500 (the ATTO benchmark on the old disk was shockingly bad at the low end compared to a WDB). Win7 32 again. One thing that had massively improved was that a particular website was hammering the system previously, taking ages to render (after I had cleaned up the browser, getting rid of unwanted add-ons etc), after the upgrade rendered in at least half the time. The relevant differences I can think of are the newer version of IE and the dGPU.