PC configuration

[apiaio]

I am going to purchase new PC. Probably the last one. I am not youngest.

Presently I have PC with i7 processor - 8 threads, 16 GB RAM and MB Z-170M-PLUS.
I have picked out
INTEL Core i7-12700K Alder Lake (25M Cache, 3,8/4,9 GHz), Procesor (BX8071512700K) - 20 threads, 32 GB RAM and MB ASROCK B660M-HDV

What I expect is shorter compilation time of the packages like e.g. qtwebengine. In the present compilation qtwebengine takes
some 2 hours and 15 minutes. I use SSD and new PC will have SSD installed also.

I will change

[pietinger]

apiaio,

please keep in mind that every compile job costs memory. How much memory depends on every package. Some packages need not more than 1 GB per job, others until 2 GB per job and I dont want to talk about "rust" ...

You surely know that you will be faster with compiling if you set a maximum of jobs that there will be no swaping (means: sometimes you are faster with -j8 instead of -j9 or higher).

Now, IF you put /var/tmp/portage also into memory, you need even more memory/job. Again you must prevent swaping.

You will buy a very fast CPU with many (logical) cores, being able to compile many jobs at the same time ... IF there is enough memory. This leads me to my personal recommendation (as user) to buy 64 GB RAM. My suggestion for this would be:

MAKEOPTS="-j20" and /var/tmp/portage tmpfs size=18G

If you will stay with 32 GB RAM you could use a configuration where you make exceptions for some packages, maybe:

MAKEOPTS="-j20" and /var/tmp/portage tmpfs size=12G

and =>

[NeddySeagoon]

apiaio,

I did that last year. Here's what I chose and why.

That CPU can use 40G RAM at 2G per thread today. You will need a minimum of 64G and two empty slots to fill later.

Do you mean SSD or NVMe?
NVMe can be 10x faster than SSD as its a faster interface.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

[apiaio]

Thanks for answers.

Why should I buy 64G RAM, when chosen CPU can use 40G RAM only? 24G will be useless.

[Spanik]

Interesting thread. But there are a few things I do not really get. I got this setup and thought it would be faster then the previous 10 years old one. But it isn't. An update @world can still need a night to complete.
- Epyc 7402P 24 cores, 48 threads
- 64GB ram (4x16GB) each on it own memory channel
- nvme Samsung 970 EVO pcie 3 x4
- Supermicro H11SSL-i all pcie lanes are separate straight to the cpu
- makeopts = "-j25"

[pietinger]

[pietinger]

P.S.: Please dont forget, you will use also other applications than emerge. If you use software which is capable of using all cores (like my "stockfish"; a chess engine) these programs ALSO needs memory for every thread ...

Yes, often 64 GB is not really needed, but it would be sad if you cant use your powerful CPU because of not enough memory in other moments ...

[C5ace]

My main box:

No tempfs. Just a 7200RPM rotating rust drive. Desktop is XFce4. Compiling is done in a Xfce Terminal Emulator.

uname -a:
AMD Ryzen 9 3950X 16-Core Processor with 32 threads and 64Gb Ram.

make.conf:
MAKEOPTS="-j33"

qlop:
2021-11-20T21:32:25 >>> dev-qt/qtwebengine-5.15.2_p20211019: 32′57″
2022-08-17T16:08:14 >>> app-office/libreoffice-7.3.4.2-r1: 16′51″
2022-07-02T11:50:37 >>> dev-lang/rust-1.60.0: 15′24″
2022-03-10T10:46:08 >>> www-client/chromium-99.0.4844.51: 1:24:03
022-08-26T16:58:10 >>> www-client/firefox-91.13.0: 13′26″
2022-07-02T11:24:16 >>> sys-libs/glibc-2.34-r13: 1′59″

Maximum memory usage was about 35Gb. No swapping.

Tried using tmpfs and found practically no change. Probably because the HDD has a 64MB cache, Xfce Desktop only uses about 600Mb RAM. This leaves heaps of free RAM for Gentoo to use as buffer/cache.
_________________
Observation after 30 years working with computers:
All software has known and unknown bugs and vulnerabilities. Especially software written in complex, unstable and object oriented languages such as perl, python, C++, C#, Rust and the likes.

[apiaio]

@pietinger
Thank you for comprehensive information. It will be 64GB.

[Spanik]

[pietinger]

[NeddySeagoon]

apiaio,

Today, with a 20 thread CPU, gcc alone can use 40G RAM.
You will want /var/tmp/portage in RAM too. Some individual packages check for 13G.

When you have the RAM the kernel buffers build products in filesystem cache anyway. /var/tmp/portage in RAM saves writes to you NVMe/SSD that will never be read.
Its not really a speed up thing.

That 53G so far. The kernel will want some space for itself, so will your desktop and any applications you want to run.
64G today is a reasonable starting point.

20 years ago I had a 1 core k6-2 with 512MB RAM. Memory and CPU requirements have grown since then :)
Expect that trend to continue, even accelerate.
With an eye to coping with that, expect to add another 64G RAM in the fairly near future.
That dictates a motherboard that can take 4x32G RAM sticks today but only two will be fitted.

CRUCIAL P1 Int. CT500P1SSD8 is marked end of life in the UK. Its a 4 lane PCIe Gen 3 device.
Your ASROCK B660M-HDV motherboard supports 1 Hyper M.2 (PCIe Gen4 x4), among other things.
You should choose a PCIe Gen 4 NVMe card for the best performance in that motherboard.
Also, your motherboard only has two DIMM slots which gives

[apiaio]

Thanks Neddy.

I will keep in mind your recommendations. I will have to look around for proper components.

[KCmovestoSD]

I have a recently upgraded system kinda similar to your build. It's a very nice system. I am curious where I could've changed my build around. I built it with only gaming in mind on Windows in mind. I game less and less now and picked up Rust and Python. Moved to Linux and haven't looked back. I "feel" like if I went team Red my build would be closer tailored to it's current use. But, it's not like I'm compiling a browser and DE daily...

It's a beast of a build you have there.

I have been thinking about increasing my amount of RAM, though I can't seem to justify spending even more money on this system.
_________________
Motherboard: PRIME-D WiFi
CPU: 12600k
RAM: 32GB 3200mhz
GPU: 6800XT & RTX 3070ti
Storage: 2x 1TB gen4 nvme, 500GB gen2 nvme

[C5ace]

Spanik:

Clean emerge:

[NeddySeagoon]

C5ace,

[Goverp]

[C5ace]

NeddySeagoon:

Don't worry. Not using anything that depends on qtwebkit. This exercise was followed by 'emerge --unmerge qtwebkit' and 'emerge -- depclean'.

Goverp:

Thanks for the info regarding time and number of cores.
_________________
Observation after 30 years working with computers:
All software has known and unknown bugs and vulnerabilities. Especially software written in complex, unstable and object oriented languages such as perl, python, C++, C#, Rust and the likes.

[apiaio]

After some testing of the new PC