bench.rb

require 'rubygems'
require 'benchmark'
require 'redis'
require 'memcached'

r = Redis.new
m = Memcached.new('localhost:11211')
watermark = 1000000

Benchmark.bm do |x|
  x.report("memcached set") {watermark.times {|num| m.set("key_#{num}", "this is just a random value")}}
  x.report("memcached get") {watermark.times {|num| m.get("key_#{num}")}}
  x.report("redis set") {watermark.times {|num| r.set("key_#{num}", "this is just a random value")}}
  x.report("redis get") {watermark.times {|num| r.get("key_#{num}")}}
end

gistfile1.txt

100000 key/value pairs

      user     system      total        real
memcached set  1.060000   2.010000   3.070000 (  8.282598)
memcached get  1.090000   1.600000   2.690000 (  7.219543)
redis set  4.570000   1.660000   6.230000 ( 11.257517)
redis get  4.230000   1.890000   6.120000 ( 10.983276)

1000000 key/value pairs

      user     system      total        real
memcached set 20.370000  17.390000  37.760000 ( 81.732159)
memcached get 20.630000  14.880000  35.510000 ( 72.285357)
redis set 40.470000  19.380000  59.850000 (112.639295)
redis get 41.800000  17.820000  59.620000 (112.828190)

1000000 key/value pairs, 2nd run

      user     system      total        real
memcached set 14.050000  17.830000  31.880000 ( 83.326390)
memcached get 17.820000  16.470000  34.290000 ( 75.529208)
redis set 42.200000  18.890000  61.090000 (114.443061)
redis get 32.880000  16.930000  49.810000 (109.049533)