Bug: Incorrect RAM values

### Describe the bug
The values for RAM and CPU on my don't match with what's displayed the acitivity monitor (Macbook Pro 2015 / macOS Catalina - 10.15.6) and in general just don't feel _right_.

I mean the RAM always stays under 8GB and rarely gets into something different like 5 or 6 while when I look at my RAM usage from the activity monitor it's never under 13GB.

The CPU usage is usually higher than what's displayed on the activity monitor and often times get above 100% (How?). Showing numbers like 400%-500%... :(

This is what's in my config:
```shell
# List of plugins
set -g @plugin 'tmux-plugins/tpm'
set -g @plugin 'tmux-plugins/tmux-sensible'
set -g @plugin 'dracula/tmux'
set -g @plugin 'nhdaly/tmux-better-mouse-mode'
#set -g @plugin "arcticicestudio/nord-tmux"

# Dracula settings
set -g @dracula-show-weather false
set -g @dracula-show-network false
set -g @dracula-cpu-usage true
set -g @dracula-ram-usage true
set -g @dracula-border-contrast true
set -g @dracula-show-powerline true
set -g @dracula-refresh-rate 1
set -g @dracula-show-timezone false
# Tmux better mouse settings
set -g @scroll-speed-num-lines-per-scroll 1

# Setting the delay between prefix and command
set -s escape-time 5
# Setting the prefix from C-b to C-a
set -g prefix C-a
# Free the original Ctrl-b prefix keybinding
unbind C-b
# splitting panes with | and -
bind | split-window -h
bind - split-window -v
# Enable mouse
set-option -g mouse on

# Tell Tmux that outside terminal supports true color
set -ga terminal-overrides ",xterm-256color*:Tc"
set -g default-terminal "screen-256color"
set -g default-terminal "tmux-256color"

# Initialize TMUX plugin manager (keep this line at the very bottom of tmux.conf)
run -b '~/.tmux/plugins/tpm/tpm'

```

### To Reproduce
Steps to reproduce the behavior:
Just install this plugin and enable CPU/RAM display

### Expected behavior
Correct CPU/RAM display

### Screenshots

### System
- OS: macOS Catalina - 10.15.6
- Tmux Version: 3.1b (Installed via `brew`)