I use a single 8GB corsair vengeance stick. Mostly got it for a bit of gaming, but useful hibernating when alot of stuff is open.

It was almost sure that trade-offs would have to be paid for the speed, bootup time for sure is a point... Maybe even power consumption.

Version: 14.1 64
desktop environment: KDE
RAM: 8gb
CPU: 4x 2.6ghz

Most of my machines have 8GB of ram or 16.

16 GB RAM on my public servers and on my main workstation. I did manage to run Slackware 14.1 32-bit on a Dell Poweredge P-III 500 MHz server with 110 MB RAM though, where most mainstream distros choked on the darn thing. One of the reasons I love Slackware and its installer.

I have 3 machines with different RAM.

Desktop - AMD 8-Core with 32G RAM, I run virtual machines.
Server - Headless Xeon-E3 with 12G RAM
HTPC - AMD Athlon X2 with 2G RAM

Zareason Limbo with 16 GB RAM. It's sweet.

1GB - 13.0 64bit
4, 8 and 16GB - 14.1 64bit

Slackware 14.1 64-bit on a 6 GB Dell Inspiron N7010, running kernel 3.18.26.
Slackware current 64-bit on an 8 GB HP Pavilion.

I am posting this from a netbook with 1G RAM and 2G swap and 32-bit Slackware 14.1 using KDE

emachine Intel Pentium D 2x 2.8Ghz with 4G RAM and 4G swap, NVIDIA 8400 running native driver, Running Slackware 14.1 x86_64, multilib, Libvirt, WINE under LVM/LUKS.
HP Pavillion AMD64 with 2G RAM and 4G of Swap. Running Slackware 14.1 x86_64, multilib, WINE. to be upgraded to 14.2 LVM/LUKs shortly.

Previously 13.37 on the laptop and also on an HP Pavillion Media Center with WinXP under VirtualBox with 512M of RAM on 1Gb memory card.

4GB desktop, KDE (sw current)
4GB 2x laptop, KDE (sw current)
3GB media server (sw14,1)
0,5GB, raspberry pi, webserver & owncloud (arm sw 14,1)

2GB eeepc (sw 13,37)

8GB on home machine, 1GB on Android phone

at home:
- laptop: 6 GB ram, Core i5, ssd, XFCE, Slack-current x64
- webserver: VM with 4 GB Ram, 2 x vCPU, Slack 14.1 x64 (runs on a Proxmox 4.x server with 16 GB ram, Core i7)
- router/firewall: 4 Gb Ram, Core2 Duo, Slack 13.x x64
- fileserver : 8GB Ram, Core2 Duo, Slack 14.1 x64

at work:
- laptop: 8 GB ram, Core i5, ssd, XFCE, Slack-current x64
- 3 fileservers: each 4 GB ram, Core2 Duo, Slack 14.x x64
- router/firewall/muli-purpose server: 8 GB ram, Core i5, Slack 14 x64
- Imaging fileserver (holds dozens of images for use with Clonezilla): 8 GB ram, Core i5, 2TB diskspace, Slack 14 x64
- monitoring system (Nagios): 4 GB ram, Core2 Duo, Slack 14 32bit (oldest system in use)

More ram is always better

16 gb of ddr3 @ 1600 mhz. Max motherboard capacity, and ofc SSD..

Home Desktop 4GB
IBM Thinkpad T43 laptop 1GB
HP zBook 15 laptop 32GB