Doctors and dentists tend to be the non-tech savvy type who'd buy the cheapest Dell or Gateway PC with minimum specs. If you engage your doctor in conversation, it's possible to upgrade their computer hardware in exchange for treatment.
Back in the days of 386 and 486 when most computer nerds had a go at building their own computer, my cousin who was a medical specialist also had a computer assembly/ retail business next door to his medical suite. It was managed by his wife. I would not be surprised if he suggested to his patients that they needed a computer for relaxation purposes or something and then promptly direct them next door to his computer shop.
I don't know where you are but most medical practices here in NZ have a pretty capable computer system as the national health system requires that a persons current medical record can be accessed by any private/public health service around the country.
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my dentist was still using an old Dell P4 with 512MB RAM... >_>
If its capable of doing the job, why change it? My favourite computers are still the monochrome 286 386
P.S. This cousin of mine genuinely believed that doctors etc deserved to be the highest paid of all professions, because people who became doctors were the elite, and there was no other profession that a doctor would lack the intelligence to perform.
Having said this I once went to a doctor who was a qualified drain layer, got sick of that , and became a dentist, he got sick of looking into peoples mouths all day, and decided to train to be a GP instead.