Learn English – Use of “nay” as an adverb

I was able to find a few instances of computer and car products being described as brutal:

one here:

Asrock 970 Pro3 promises brutal performance with 8-core AMD CPUs.

and another here:

The Mazda 6 MPS is a more refined, larger car that offers more space and luxury together with the brutal performance of it's [sic] turbocharged engine.

I'll point out that I had to wade through some irrelevant content (much of it using brutal with a negative connotation) in order to find these. You will also notice that these examples are not from major marketing campaigns. I also searched YouTube for "brutal performance" and got lots of hits for loud cars (most of the results were for rock music videos).

The intended meaning of brutal in these instances is probably some combination of strong and rugged, or perhaps even manly or interested more in power than the feelings of others. How it is actually interpreted will vary from person to person, but some people will probably receive a negative feeling from the word (I am reminded of a list of adjectives in Hobbes' Leviathan, "solitary, poor, nasty, brutish, and short").

As for whether it is okay to use the word in marketing, that all depends on the image that you want to put forward. Sometimes a company is okay with being seen as focused on raw power rather than on other positive attributes (perhaps to attract customers who think, "I don't care if my engine is quiet, as long as it's fast!") In that case, I would say brutal is just fine to use.

Other words (possibly with different connotations) that might appear in similar marketing outlets are:

• savage
• beastly
• unrestrained
• rugged
• powerful

OED's entry for the usage OP is concerned with says...

Intimating that the sentence expresses an extreme case of a more general proposition implied (= French même). Prefixed (in later use often parenthetically postfixed) to the particular word, phrase, or clause, on which the extreme character of the statement or supposition depends.

It also goes on to say...

This use, now the prevailing one in Eng., is foreign to the other Germanic langs. It is rare in purely dialectal speech, and (though a natural development of 8) seems not to have arisen before the 16th c.

(OED's definition 8 refers to a largely obsolete usage where even = ‘namely’, ‘that is to say’, ‘just’, ‘nothing else but’, ‘to be sure’, ‘forsooth’).

Note that although they're very similar in meaning, there's a slight distinction between...

1: She even forgot my birthday
2: She forgot even my birthday

In #1, it's implied she performed other different actions besides forgetting my birthday (maybe she ate my last Rolo, for example). In this case, even modifies the entire phrase forgot my birthday.

But #2 more specifically implies that she forgot other things (not necessarily even relating to me).

There's nothing at all "odd" about OP's "Will you even be there?" (it's emphasising that not only might you not do something when you're "there" - there's some question as to whether you will be there at all).

OP's "Who even is she?" and "What even is that thing?" are highly unlikely constructions that would probably be considered unacceptable/substandard by most native speakers. The reason for this is that even never really modifies the verb to be at all - it modifies whatever comes next, as in...

"Can't you even be polite?" (If you can't be/act how I want, can you at least be polite?).
"I can't even be bothered to reply" (I can't do much at all, specifically not bother to reply).