Processor: 1 GHz or faster
Hard disk : 16 GB for 32-bit & 20 GB for 64-bit
RAM: 1 GB for 32-bit & 2 GB for 64-bit
Graphics : Microsoft Direct X 9 capable graphics processor
The requirements are quiet low and and 10year old hardware have better capability than above requirements (Except PAE, NX, and SSE2 ). Hence we can expect some sort of variation in that, but be assured that you will be able to upgrade your Windows 7/ Windows 8/ Windows 8.1 PC to Windows 10.
Official Windows 10 System requirements
Processor: 1 gigahertz (GHz) or faster
RAM: 1 gigabyte (GB) (32-bit) or 2 GB (64-bit)
Free hard disk space: 16 GB
Graphics card: Microsoft DirectX 9 graphics device with WDDM driver
A Microsoft account and Internet access
Some old 64bit CPU’s without PAE, NX, and SSE2 may not be able to install Windows 8 Developer preview. It is also desired to have a monitor with resolution at-least 1024 x 768 pixels and active internet connection for downloading upgrade package and apps. The technical preview will expire on April 15, 2015. Stay tuned for more windows 10 news /updates as in the upcoming week Microsoft is going to reveal many more things.
Processor: 1 gigahertz (GHz) or faster
RAM: 1 gigabyte (GB) (32-bit) or 2 GB (64-bit)
Free hard disk space: 16 GB
Graphics card: Microsoft DirectX 9 graphics device with WDDM driver
A Microsoft account and Internet access
Some old 64bit CPU’s without PAE, NX, and SSE2 may not be able to install Windows 8 Developer preview. It is also desired to have a monitor with resolution at-least 1024 x 768 pixels and active internet connection for downloading upgrade package and apps. The technical preview will expire on April 15, 2015. Stay tuned for more windows 10 news /updates as in the upcoming week Microsoft is going to reveal many more things.