In the perfect world I could get everything I want, however budgets for new laptops are low so I normally can get a user a laptop + additional RAM (to at least 4Gb). This has been mostly motivated by Vista's RAM eating abilities - however I have always thought that putting in a faster drive (i.e. not the standard 5400rpm drive) would have a bigger benefit.
What would you put (more RAM or faster disk) in for laptops running Vista/Office AND Win7 or XP/Office (since they are less of a RAM hog)?
More RAM is the way to go. Running multiple applications, that extra RAM will do a lot more good than a faster HDD which is still physically restricted to it's single spindle.
Once you run of RAM and the OS starts paging to the HDD, your system will crawl irregardless of how fast your HDD is.
Identify the most common bottleneck (e.g. with perfmon.exe) and base your decision on that.
I would generally choose faster disks since I witness IO bottlenecks more often, especially when machines are loaded with the Corporate Performance Taxes (anti-virus, Landesk, Sanctuary etc)
It's worth noting that "Vista's RAM eating capabilities" are overrated. Vista does something very sensible: It uses the RAM if it's available. If the RAM is otherwise unused, why shouldn't Vista use it to cache recently used data? You don't gain anything from having large amounts of unused RAM. And of course, if your applications start needing more RAM, Vista will start releasing some of what it's using. So Vista isn't that bad.
Apart from that, it depends on your usage. How much is the harddrive used? How often are applications launched, how often do they need to access a lot of files?
For a lot of people, the usage pattern is something like this:
And usually, almost all the time is being spent on #3.
Occasionally, the antivirus scanner may choose to poke at a few files, or Vista will start indexing the harddrive, but in general, once the system is up and running, RAM becomes the most important aspect. But of course there are areas of work where this isn't true, so it depends.
On the other hand, how much RAM do your users need? Most applications run fine with 2GB RAM. Even on Vista, and even with a handful of background processes. If the system will never need more than 2GB, plugging in 4GB is rather pointless.
Ultimately, it depends on the software you're putting on the system, and what the users are going to do with it. We can't answer that one for you. :)
One thing that I wish I'd considered when it came to purchasing my laptop, was hibernation. I chose 3GB RAM and didn't worry too much about disk speed. Shutting down the PC is slow, because of the hard drive, but writing 3GB of RAM to hard disk to hibernate is also slow. Its a lose-lose.
I'd go for 2 GB of RAM and a faster hard disk.
There's really no point putting in much more RAM than that just for running Office, but a fast hard disk can make loading the O/S and applications feel much faster.
Be warned, a faster disk will massively eat your battery life. Although it will provide notifiable performance improvements for certain tasks.
The performance difference between a "faster" and "slower" hard disk when comparing laptop drives is not significant. Keep this in mind.