The early (pre-conference) talk about the hardware of the next gen systems sounded like they would just be an $80-150 upgrade for my 2010 PC. The rumored CPU didn't sound all that impressive (and they didn't talk about what clockrate or how many cores it had during the conference), but after it became clear they use 8GB's of GDDR5, I'm not so sure about that. That stuff is expensive and I don't know about any consumer grade motherboards that use or even support that, so that'll probably keep up with high end PC's for several years. Obviously we'll be in the same situation we're in right now in another 7 or so years, but I don't think the memory will be the issue with this machine (like it was throughout the entire cycle of this generation - 512MB wasn't much even in 2005 and the PS3 could only use 256MB out of those 512 if I recall correctly, that shit's been devastating to developers), but the CPU worries me a little, 1.6 ghz doesn't sound like much, even if it is 8 cores. That sounds like a potential issue down the line, it's not like consumer grade 3ghz 8 core CPU's are prohibitively expensive today.
Clock speeds and number of cores are not necessarily useful points of comparison when talking about vastly different chip architectures. Examples include Nvidia vs ATI/AMD video cards, significantly lower clock speed multicore processors that are much faster and more efficient than the highest clocked Pentium IVs of the past, and lower clocked dual-core consumer Intel processors that were faster than the 360's 3.2ghz triple-core CPU.
I'm wondering if the PS4's processor is a result of joint development with IBM, like Cell was?