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RAM

Characteristics

Name Unit Default value Description Example
units None 1 RAM strip quantity 2
usage None See Usage See usage ..
capacity GB 32 Capacity of a ram strip 12
density GB/cm2 0.625 Size of the die per Go of a ram strip 1.25
process nm None Engraving process (Architecture) 25
manufacturer None None Name of the ram manufacturer Samsung
model None None .. ..

Complete

The following variables can be completed

density

if process or/and manufacturer are given, density can be retrieved from a fuzzy matching on our ram repository. If several ram matches the given process or/and manufacturer the maximizing value is given (in terms of impacts).

Manufacture impact

For one RAM bank the manufacture impact is:

\[ \text{RAM}_\text{manufacture}^\text{criteria} = (\text{RAM}_{\text{capacity}} / \text{RAM}_{\text{density}}) * \text{RAM}_\text{manufacture_die}^\text{criteria} + \text{RAM}_\text{manufacture_base}^\text{criteria} \]

with:

Constant Units Value
\(\text{RAM}_\text{manufacture_die}^\text{gwp}\) kgCO2eq/cm2 2.20
\(\text{RAM}_\text{manufacture_die}^\text{adp}\) kgSbeq/cm2 6.30E-05
\(\text{RAM}_\text{manufacture_die}^\text{pe}\) MJ/cm2 27.30
\(\text{RAM}_\text{manufacture_base}^\text{gwp}\) kgCO2eq 5.22
\(\text{RAM}_\text{manufacture_base}^\text{adp}\) kgSbeq 1.69E-03
\(\text{RAM}_\text{manufacture_base}^\text{pe}\) MJ 74.00

Note: If there are more than 1 RAM bank we multiply \(\text{RAM}_\text{manufacture}^\text{criteria}\) by the number of RAM bank given in units.

Usage impact

Both power consumption and consumption profile are implemented.

Consumption profile

The RAM consumption profile is of the form : consumption_profile(workload) = a * capacity

As a first approximation, we use a uniform consumption profile since the stress test data used show a rather uniform consumption. Consequently, the workload won't be used.

cp_ram.png

New stress test data specifically on RAM calls should be conducted to specify this consumption profile.

Determining the parameters

To determine a we averaged the electrical consumption of RAM per GB. With the process we came up with a=0.284

Capacity is either given by the user or the default value is used.

consumption_profile(workload) = 0.284 * capacity