It quite easy, and relatively efficient to calculate multiple-period moving averages concurrently, requiring just a single pass over the data:

#! perl -slw
use strict;
use List::Util qw[ sum ];

our $LOW   //= 10;
our $HIGH  //= 100;
our $LIMIT //= 0.85;

my %seqs = map{ $_ => [] } $LOW .. $HIGH;

for my $i ( 1 .. 1e6 ) {
    my $value = rand 1;
    for my $period ( $LOW .. $HIGH ) {
        if( @{ $seqs{ $period } } < $period ) {
            push @{ $seqs{ $period } }, $value;
        }
        else {
            shift @{ $seqs{ $period } };
            push @{ $seqs{ $period } }, $value;
            my $ave = sum( @{ $seqs{ $period } } ) / @{ $seqs{ $period
+ } };
            if( $ave > $LIMIT ) {
                printf "Possible $period period cluster (ave:%.3f)".
                       "at %d through %d\n",
                    $ave, $i - $period, $i;
            }
        }
    }
}

__END__
C:\test>junk81.pl
Possible 10 period cluster (ave:0.869)at 16470 through 16480
Possible 10 period cluster (ave:0.855)at 16471 through 16481
Possible 11 period cluster (ave:0.858)at 16470 through 16481
Possible 10 period cluster (ave:0.857)at 101204 through 101214
Possible 10 period cluster (ave:0.852)at 101205 through 101215
Possible 10 period cluster (ave:0.856)at 146170 through 146180
Possible 10 period cluster (ave:0.866)at 211311 through 211321
Possible 10 period cluster (ave:0.864)at 323774 through 323784
Possible 10 period cluster (ave:0.868)at 442882 through 442892
Possible 12 period cluster (ave:0.850)at 452199 through 452211
Possible 12 period cluster (ave:0.851)at 452200 through 452212
Possible 13 period cluster (ave:0.856)at 452199 through 452212
Possible 10 period cluster (ave:0.852)at 557989 through 557999
Possible 10 period cluster (ave:0.863)at 700401 through 700411
Possible 10 period cluster (ave:0.858)at 759150 through 759160
Possible 10 period cluster (ave:0.862)at 759151 through 759161
Possible 11 period cluster (ave:0.864)at 759150 through 759161
Possible 10 period cluster (ave:0.853)at 759152 through 759162
Possible 11 period cluster (ave:0.866)at 759151 through 759162
Possible 12 period cluster (ave:0.868)at 759150 through 759162
Possible 13 period cluster (ave:0.853)at 759149 through 759162
Possible 13 period cluster (ave:0.850)at 759151 through 759164
Possible 14 period cluster (ave:0.852)at 759150 through 759164
Possible 10 period cluster (ave:0.866)at 786191 through 786201
Possible 10 period cluster (ave:0.851)at 805682 through 805692
Possible 10 period cluster (ave:0.864)at 965272 through 965282
Possible 10 period cluster (ave:0.853)at 992279 through 992289
Possible 10 period cluster (ave:0.886)at 992281 through 992291
[download]

That took just about 4 minutes to calculate 90 different moving averages over a million data points. There's no IO invloved, but as it only requires a single pass, that's an unavoidable constant anyway.

You can obviously do less and non-consecutive periods.