BUG: why arrow no affect in Intel chips？

[wonb168]

Pandas version checks

• I have checked that this issue has not already been reported.

• I have confirmed this bug exists on the latest version of pandas.

• I have confirmed this bug exists on the main branch of pandas.

Reproducible Example

import pandas as pd

pd.options.mode.copy_on_write = True

def ensure_arrow_format(df):
        if not isinstance(df._mgr, pd.core.internals.ArrayManager):  # 检查是否已经是 Arrow 格式
            return pa.Table.from_pandas(df).to_pandas()
        return df

Issue Description

I updated pandas from 2.1.4 to 2.2.3,
and open copy on write,
and convert to arrow before df merge,
then the cost from 61s to 36s,
faster.

Expected Behavior

My pc is mac mini m2, from 61s to 36s,
but in x86 centos or win10, only from 109 to 102,
why no affect in intel cpu?

Installed Versions

pandas 2.2.3

[rhshadrach]

Thanks for the report. Can you provide a fully reproducible example. We need the DataFrame you are operating on to be able to look further into the issue.

pa.Table.from_pandas(df).to_pandas()

In addition, it would be helpful to report benchmarks for each of these two operations.

pa_table = pa.Table.from_pandas(df)
result = pa_table.to_pandas()