Extract Text

You can add a custom column in the query editor with this formula.  It worked with your sample data (replace [TextColumn] with your actual column name), but you may have to adapt it, if there are scenarios not covered.

= List.First(List.Transform(List.Select(Text.Split([TextColumn], " "), each Text.Contains(_, "GB")), each Text.BeforeDelimiter(_, "GB") & "GB"), ", ")

If this works for you, please mark it as the solution.  Kudos are appreciated too.  Please let me know if not.

Regards,

Pat

Anonymous 

For DAX you can use calculated column

Memory Column = 
VAR GbStart = SEARCH("GB", [Column1])
VAR PrevSpace = SEARCH(" ", [Column1]) + 1
VAR StartPosition = IF(PrevSpace > GbStart, 1, PrevSpace)
VAR TextLen = GbStart - StartPosition + 2
RETURN
IF(StartPosition = 0, LEFT([Column1], TextLen), MID([Column1], StartPosition, TextLen ))

Here is a basic version without any error checking. Add that as needed.

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("hY/LCsIwFER/ZejKQgN5EeKymhKLaSm3KoHS//8Nm8Sq4MLVLM65c5llqS4ThPEnHERMWUNS1JjOKjAhLedUrc3b+id1pUsUqpnUnN8YwfXDkJWMMzkqBXdvA6N2vCJaOEc6O/ZbmfvRh+5XSr+U3MzUgYJ1xq/qvjw0em8zxuDBqAF1HrOjdoD029G+L7dtA1PW0J+B3HAeYKt1fQI=", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [Column1 = _t]),
    #"Added Custom" = Table.AddColumn(Source, "Custom", each 
    let g = Text.PositionOf([Column1],"GB"),
    sp = Text.PositionOf([Column1]," "),
    st = if sp<g then Text.Range([Column1],sp+1,g-sp+1) else Text.Start([Column1],g+2) 
in 
    st
)
in
    #"Added Custom"

not sure if you are trying to implement a column of a measure, but this is the pseudocode to extract memory from your strings: