spec for new pc

Windows != Linux

So memory requirements are different.

Min memory I use for any machine these days (Mac/Windows/Linux) is 32G.

If you ever plan on running OSX/Mac or Windows, 32G is best minimum, more if you'll be running repeated video transcodes or brutal compressors like zstd... which will use up whatever memory is available.

I agree with David.

You didn't mention displays (monitors) so I will just throw this out there:
Every workstation I set up in my office has 2 (sometimes 3) displays.
There's no question, if you have the desk space and budget for 2 displays it is well worth the investment. Just make sure your workstation supports 2 displays.

It depends on what type of software you run.

My computer have only 8 GB RAM, but work fine for my use case. I only use Google Chrome (with lot of tabs open, just counted, 52 tabs atm), Microsoft Visual Code Studio and SSH Terminal.  Some times i run VM on my computer for testing, so far all works fine. In future when i purchase a new PC, i may go with more RAM as having more always helps.

Here is my memory usage

boby@sok-01:~$ free -m
              total        used        free      shared  buff/cache   available
Mem:           7970        5686         250         608        2034        1404
Swap:          9536         119        9417
boby@sok-01:~$

Select allOpen in new window

When getting new PC, make sure you have SSD, that make a big difference. As for CPU, most CPU these days are faster, so you should be fine.

If you do Anrdoid Development or something like that you may need lot of RAM and  good CPU too.

Since EE's search system is so broken (hint EE... seriously... fix this...) I can't find any of the recent questions related to this topic.

In my case I'm run an iMac, with only a Browser + Email client + few other light weight apps running + many ssh connections to servers...

Most of the time, just this minor load uses 17G of memory, so if I'd purchased 16G, my system would be swapping... doing... virtually no work...

If I run many zstd compressions (happens every night) or a video transcodes (especially HEVC with massive lookahead buffers), my memory usage shoots up to 32G in a few seconds.

Guideline: Easier to buy memory to begin with, rather than run out + require more.

My rule today: 32G minimum or if machine will take more, max out memory at time of purchase.

You can never have to much memory, if you're doing any time of memory intensive work.

Random Aside...

I just fired up a simple DVD rip, of a film to watch later, memory usage on system instantly jumped by 4G.

This suggest the DVD ripper code is almost surely... poorly conceived + poorly written...

And... this is a great example of how sloppy developers can eat up massive amounts of memory through poorly crafted code.

My 2 cents...

• CPU:  Quad core minimum.  Don't fall for the cheaper i7s and i5s with just 2 cores.  The processing power can be much lower.  Check CPU performance at Passmark (see below). 
• Memory: 16gb should be OK for code editors, web browsers, office apps and simulators.  If you plan to run virtual PCs for testing apps and simulating Sites/servers then 32gb would be my minimum. Memory speed may be a consideration too for high intensity apps or to get best performance from high speed components.
• Primary Disk: Should be a PCIe NVME SSD (not a SATA NVME) SSD or Sata SSD.  Sata drives are much slower (while better than spinning drives).  Even the PCIe drives vary widely in performance (although all are faster than either Sata).  Passmark is you pal here too.  
• Video:  Onboard video these days is just fine except for more than 2 monitors, gamers or CAD/Design work. If you fit there, you can check video card performance at Passmark.  Adding a higher performance video at this time can be costly, due to current chip shortages.  
•  Monitor:  A consideration only if you plan to buy a laptop.  For desktops you can add or change them when ever you want.   Large monitors (or multiple monitors) can be handy if you frequently need many windows open.  Just about any system can handle 2.  For more, you may need a video card. 

Not sure if you are building new, buying prebuilt or configuring one from a PC maker.  But in all cases you should check/compare/balance CPU, Disk, Memory and video performance.  It makes no sense to spend $$ more for a higher speed disk, for example, if the chipset or memory is going to throttle it.  

Passmark mark has benchmarks and info on most components: https://www.cpubenchmark.net/CPU_mega_page.html# 
 

@yujin boby
That 8 GB PC is swapping a whole lot.  You should have 16 GB or more.  Chrome with 52 tabs is bloated.  You probably should close some or switch to a less bloated browser, maybe Pale Moon or K-Meleon.  If you stick with Chrome, you probably need 20 GB or more since you have 8 GBM RAM and 9 GB in swap.  That much swap is wasteful and slows your system down a lot.  Upgrade to 16 GB and close a few tabs to speed up your system.  You'll notice it when you no longer swap.

##
Mac software is more bloated.  You do need more RAM with Macs, but you can survive with 16GB On Linux or Windows when a Mac actually needs 24 GB.  8GB is for the very casual home web users, such as grandparents and such, and I still wouldn't recommend less than 16 GB these days because of all the browser bloat.

What exactly are you going to run? What is your price range?  That determines what you should get.  Desktop?  Laptop?  Software requirements?  Your question is too open ended for proper suggestions.

serialband says it well : post more info on what you want to do, and price range.
Also, do you you need a lot of disk space, and special hardware- or soft?
if you want to upgrade a bit, i still opt for a desktop ( also cheaper  than a laptop)
you can also go in desktops for prebuild ones, - have a look at Asus  : Desktops | ASUS USA 

I will be doing development in java python nodejs and java script and test applications in microservice

is this good
https://www.asus.com/us/Commercial-Desktop/ExpertCenter-D7-SFF-D700SA/

That should be fine, just get at least 16 GB RAM.  You can use 32 GB if you want to do more.

This one, if your interested in ASUS, would be a better config.  More powerful CPU and more memory.  

https://store.asus.com/us/item/202010AM080000003/A38034-ASUS-ExpertCenter-D700SA%2C-Small-Form-Factor-Desktop-PC%2C-Intel-Core-i7-10700%2C-16GB-DDR4-RAM%2C-512GB-PCIe-SSD%2C-TPM-2.0%2C-3-Year-Onsite-Service%2C-Wi-Fi-6%2C-Windows-10-Professional%2C-Black%2C-D700SA-XB701

Here is a similar one from Dell

https://www.dell.com/en-us/work/shop/desktops-all-in-one-pcs/optiplex-7080-small-form-factor/spd/optiplex-7080-desktop/s016o7080sffus?view=configurations

prebuild ones tend to be cheaper than the self built ones

nowadays - most hardwares are ok; it only depends on the softwares you want to run
as long as there are no heavy cpu  and resources users -  you're fine with "normal spec"

hi what will be the spec for window 11

here they are :  The Windows 11 system requirements aren't the end of the world (xda-developers.com) 

i need spec for window 11

Here is a list of AMD products with Windows 11 support
     https://www.amd.com/en/support/kb/release-notes/rn-ryzen-chipset-3-10-08-506

Here is a list of Intel supported processors
     https://docs.microsoft.com/en-us/windows-hardware/design/minimum/supported/windows-11-supported-intel-processors

Here is a list of motherboards compatible with windows 11
     https://www.pcguide.com/windows-11/guide/motherboard-compatibility-list/

Note:   Intel 10th gen processors and newer use a newer socket and chipset than the 8th and 9th gen CPUs.  

A good idea would be to check the mobo / GPU manufacturer site for the products you select to make sure they have Windows 11 drivers as a last step, before buying.  Actually I suggest you do that for everything that requires a driver that you plan to buy (sound cards, WiFi, etc.).  No windows 11 driver = it probably won't work.

u had a more or less similar Q :  Solved: best bang for the buck pc parts | Experts Exchange (experts-exchange.com) 

I think the issue now is which products will work for Windows 11.